Đáp án là C. noticeably: một cách đáng kể >< invisibly : một cách không đáng kể unwaveringly : một cách vững vàng; wildly: một cách dữ dội;; unpredictably: không lường trước được

Part 2:

Khi viết bài học sinh cần chú ý:

- Đoạn văn phải bao gồm ba phần chính: Opening: Dẫn dắt và đưa ra câu chủ đề (topic sentence); Body: Triển khai ý; Conclusion: Đưa ra câu kết luận ( nhắc lại ý của topic sentence )

- Chú ý cách dùng từ, cấu trúc câu, thì của động từ. Và thường với những bài viết luận như này, chúng ta sử dụng thì hiện tại đơn giản.

Sample 1:

It is known that animals play an important role in our environment. However, many animal species are in danger of extinction. The reason causing the decrease in the number of animals is mainly from human beings. It is high time we had to take some measures to protect endangered animals. Firstly, people should be educated about the importance of wild animals in maintain the biodiversity. They should be told about the things that threat the safety of wildlife so that they can avoid doing them. Secondly, the governments all over the world should set up national parks and wild-life preserves as many as possible. Thanks to these natural and safe places, animals will have a suitable habitat and good conditions to survive. Last but not least, each nation must enforce stricter law with more serious punishment- capital punishment, for example - to prevent people from poaching rare and valuable animals. In general, protecting wild animals is essential and each of us has the responsibility for protecting and saving endangered species before it is too late.

Sample 2:

There are a number of measures that should be taken to protect endangered animals. First, people should organize different activities to raise people's awareness of the urgent needs to protect these animals. For example, they hold international conferences, seminars and forums about the great importance of ecology and biodiversity. At the same time, they should appeal for government agencies in the world to contribute to the programs of protecting and preserving plants and animals that are driven to the verge of extinction. In addition, people should contribute to the fund of preserving the earth's valuable natural resources for the future generations. Besides these, governments should enact laws to ban activities that can damage or destroy the nature. If these measures are taken, our planet might be a peaceful and beautiful place for all kinds of beings to live in.

According to the passage, what did Carson primarily study at Johns