B. Read the passage carefully, then choose the correct answer.

A higher reading rate, with no loss of comprehension, will help you in other subjects as well as in English, and the general principles apply to any language. Naturally, you will not read every book at the same speed. You would expect to read a newspaper, for example, much more rapidly than a physics or economics textbook — but you can raise your average reading speed over the whole range of materials you wish to cover so that the percentage gained will be the same whatever kind of reading you are concerned with. The reading passages which follow are all of an average level of difficulty for your stage of instruction. They are all about five hundred words long. They are about topics of general interest which do not require a great deal of specialized knowledge. Thus they fall between the kind of reading you might find in your textbooks and the much less demanding kind you will find in a newspaper or light novel. If you read this kind of English, with understanding at four hundred words per minute, you might skim through a newspaper at perhaps 650 – 700 words per minute while with a difficult textbook you might drop to two hundred or two hundred and fifty. Perhaps you would like to know what reading speeds is common among native English-speaking university students and how those speeds can be improved. Tests in Minnesota, USA, for example, have shown that students without special training can read English of average difficulty, for example, Tolstoy‘s War and Peace in translation, at a speed of between 240 and 250 words per minute with about seventy percent comprehension. Students in Minnesota claim that after twelve-half-hour lessons, once a week, the reading speed can be increased, with no loss of comprehension, to around five hundred words per minute.

The reason for all the changes being made _______ to us.