20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 11)

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions.

The founding of the Radium Institute in 1914 made her dream coming true.

Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions.

Let’s to get up early to go for a walk before breakfast.

Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions.

My manager wanted to know that whether I was taking much money with me to France.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Rodney ______ for the company for very long before he was promoted.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

John said he ______ to visit me the day after.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

John ______ taking the money, but nobody believed him.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

The director deputy ______ the responsibility for organizing meetings and conferences.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

He expected ______ for an Oscar, but he wasn’t.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Some candidates failed the oral exam because thay didn’t have enough ______

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

It was on March 19th, 1876 ______ the first telephone call was made.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

You should use this cream ______ the sun from damaging your skin.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

My brother ______ while he ______ his bicycle and hurt himself.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

The viewers ______ to his suggestion with a big clap.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Mr. Kane finds it hard to ______ friendly relations with his thoughtless neighbors.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Nothing unusual happened, _______?

Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.

Anne: “Do you think we’ll have good weather?”

  Susan: “ ____________.”

Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.

Anna: “I think we should recycle these bags. It will help protect the environment.”

  John: “ __________________. ”

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

We can use either verbal or non-verbal forms of communication.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

In my attempt to win a place at university, I am under a lot of pressure.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

In Western culture, it is polite to maintain eye contact during conversation.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

There have been significant changes in women’s lives since the women’s liberation movement.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

“I am sorry, Jean. I broke your bicycle”, said John.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

“Shall I carry the suitcase for you, Mary?”, said John.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

It is said that he broke the world record.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

A waitress served us. She was very impolite and impatient.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

Mary lost the ticket. She didn’t go to the concert.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 31 to 35. Fill in the appropriate word in question 31

          In Japan, politeness and good manners are very important and business meetings are very formal. Business cards are also important and they (31) ________ these at the beginning of a meeting. They always look at them carefully, so you should do the same as they might think you're rude if you don't. A lot of communication is non-verbal. They are very good listeners and may ask a lot of questions to (32)_____ they understand everything.

          In a conversation they wait longer before they reply than westerners do, so it's important (33)_______ speak in those long pauses but to wait for their reply. In their culture it's rude to ask direct questions or to say 'No' or 'I disagree'. In business it takes a long time to (34)_______ a decision because they have to ask everyone in the company. When they say 'Yes' it may mean 'I understand', not 'I agree', and when they smile it might be because they don't know (35)_______ to say.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 31 to 35. Fill in the appropriate word in question 32

In Japan, politeness and good manners are very important and business meetings are very formal. Business cards are also important and they (31) ________ these at the beginning of a meeting. They always look at them carefully, so you should do the same as they might think you're rude if you don't. A lot of communication is non-verbal. They are very good listeners and may ask a lot of questions to (32)_____ they understand everything.

          In a conversation they wait longer before they reply than westerners do, so it's important (33)_______ speak in those long pauses but to wait for their reply. In their culture it's rude to ask direct questions or to say 'No' or 'I disagree'. In business it takes a long time to (34)_______ a decision because they have to ask everyone in the company. When they say 'Yes' it may mean 'I understand', not 'I agree', and when they smile it might be because they don't know (35)_______ to say.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 31 to 35. Fill in the appropriate word in question 33

          In Japan, politeness and good manners are very important and business meetings are very formal. Business cards are also important and they (31) ________ these at the beginning of a meeting. They always look at them carefully, so you should do the same as they might think you're rude if you don't. A lot of communication is non-verbal. They are very good listeners and may ask a lot of questions to (32)_____ they understand everything.

          In a conversation they wait longer before they reply than westerners do, so it's important (33)_______ speak in those long pauses but to wait for their reply. In their culture it's rude to ask direct questions or to say 'No' or 'I disagree'. In business it takes a long time to (34)_______ a decision because they have to ask everyone in the company. When they say 'Yes' it may mean 'I understand', not 'I agree', and when they smile it might be because they don't know (35)_______ to say.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 31 to 35. Fill in the appropriate word in question 34

          In Japan, politeness and good manners are very important and business meetings are very formal. Business cards are also important and they (31) ________ these at the beginning of a meeting. They always look at them carefully, so you should do the same as they might think you're rude if you don't. A lot of communication is non-verbal. They are very good listeners and may ask a lot of questions to (32)_____ they understand everything.

          In a conversation they wait longer before they reply than westerners do, so it's important (33)_______ speak in those long pauses but to wait for their reply. In their culture it's rude to ask direct questions or to say 'No' or 'I disagree'. In business it takes a long time to (34)_______ a decision because they have to ask everyone in the company. When they say 'Yes' it may mean 'I understand', not 'I agree', and when they smile it might be because they don't know (35)_______ to say.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 31 to 35. Fill in the appropriate word in question 35

          In Japan, politeness and good manners are very important and business meetings are very formal. Business cards are also important and they (31) ________ these at the beginning of a meeting. They always look at them carefully, so you should do the same as they might think you're rude if you don't. A lot of communication is non-verbal. They are very good listeners and may ask a lot of questions to (32)_____ they understand everything.

          In a conversation they wait longer before they reply than westerners do, so it's important (33)_______ speak in those long pauses but to wait for their reply. In their culture it's rude to ask direct questions or to say 'No' or 'I disagree'. In business it takes a long time to (34)_______ a decision because they have to ask everyone in the company. When they say 'Yes' it may mean 'I understand', not 'I agree', and when they smile it might be because they don't know (35)_______ to say.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

Which of the following would be the best title for the passage?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

What does the author say about speech?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

The phrase “impinge upon” in paragraph 1 is closest in meaning to _______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

The word “it” in paragraph refers to _______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

Applauding was cited as an example of _______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

Why were the telephone, radio, and television invented?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

        Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver's cultural perceptions. In some cultures, applauding in a theater provides performers with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

        Although signals, signs, symbols and gestures are very useful, they do have a major disadvantage. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction come to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no doubts but that there are more means of communication on the horizon.

It may be concluded from this passage that _______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

What does the passage mainly dicuss?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word “adversely” in the first paragraph is closest in meaning to ______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

It can be inferred from the first paragraph that ______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word “these” in the second paragraph is closest in meaning to _____.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

For which of the following reasons can natural pollutants play an important role in controlling air pollution?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

According to the passage, human- generated air pollution in localized regions ______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word “localized” in the third paragraph is closest in meaning to .

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

According to the passage, the numerical value of the concentration level of a substance is only useful if .