阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词-优题课

人们对于学生网上交友持不同意见，请用英语写一篇关于学生网上交友的短文，介绍人们的不同意见，并表达自己的看法。
赞成的理由是：1 广交朋友；2 可自由表达思想；3 利于外语学习。
反对的理由：1 浪费时间；2 影响学习；3 可能上当受骗
你的看法是：......
注意：
1 文章必须包括以上全部内容。
2 词数100词左右。
3 参考词汇：网络朋友on-line friend ，上当受骗 to be cheated .

With the __________ （develop）of industry, air pollution is getting more and more serious. In Beijing, many people suffer different kinds of illnesses because _________ air pollution. Air pollution is caused by the following_________: about half of the problem is caused by vehicles. There are more and more cars, buses on the roads, and they give off _________( poison) gases. 25% of air pollution is caused by factories. Another factor is the smokers. Smoking not only does harm to their health ________ to others._________ these, about 10% of air pollution is caused by other reasons. We should take some measures to fight _________ pollution. New fuel can be used to take _________ place of gas. We can plant more trees. If everybody realizes the ________（important）of environment and does something to stop pollution, the problem will__________（solve）.

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。
The Sahara Desert,(cover) most of North Africa, is the largest desert in the world. From north to south the Sahara is between 800 miles 1200 miles and is at least 3000 miles from east to west. Due to the large size of the Sahara, Africa is split into two regions: thatlies above or forms part of the Sahara and the rest of Africa south of the Sahara. On the west, the Sahara is (border) by the Atlantic Ocean and on the east by the Red Sea, and to the north are the Atlas Mountains and Mediterranean Sea. Over 25 percent of the Sahara's surface is covered by sand sheets and dunes.
The Sahara's climate consistsbasically two sub-climates ,a dry subtropical climate in the north and a dry tropical climate in the south. The dry tropical climate is(general) characterized by mild, dry winters, a hot dry season just before the rainy season, and an annual temperature cycle. The dry subtropical climate, ,is characterized by (annual) high temperature ranges, cold winters, hot summers and two rainy seasons. There is a narrow strip in the western portion of the Sahara, the coast, which generally has cool temperatures (compare) to the rest of the Sahara because of the influence of the cold Canary Current.

Most Americans don’t like to get advice __________members of their family. They get advice from “________(strange)”. When they need advice, they don’t usually go to people they know. _________ many of them write letters to newspapers and magazines ________ give advice on many different subjects, _________ (include) family problems, the use of language, health, cooking, child care, clothes, and even on how_________ (buy) a house or a car.
Most newspapers regularly print letters from__________ (read) with problems. Along with the letters _________ are answers written by people who are supposed to know how to solve such problems. Some of these writers are doctors,__________ are lawyers or educators. But two of the most famous writers of advice are women without special ________ (train) for this kind of work.

When you are in England you must be very careful in the streets _______ the traffic drives on the left. Before you cross a street you must look to the right first__________ then the left. In the morning and in the evening when people go to or come from _________, the streets are very busy. Traffic is most ________ （danger） then.
When you go by bus in England, you have to be careful,_______. Always remember the traffic moves on the left. So you must be careful._______ （have） a look first, or you will go _________ wrong way.
In many English cities, there are big buses_________ two floors. You can sit on the ________ （two） floor. From________ you can see the city very well. It’s very interesting.