1. 我们的班长被认为是我们班上最好的学生。(regard) 2. 现代科学技术的发展使我们的社会发生了巨大变化。(bring about) 3. 如果不练习说英语，你就学不好英语。(without) 4. 每个人都应该知道如何遵守交通规则，这样就能避免交通事故。(avoid) 5. 我已经认识到只有努力学习，才能学好英语。(realize) 6. 你在课堂上应集中注意力学习，否则你就不能理解老师所讲的内容。(concentrate) 7. 他又把邻居家的窗户打破了，这使他的父母很生气。(which) 8. 良好的健康取决于好的食物、运动和充足的睡眠。(depend on) 9. 那个学期他阅读的不是一本英语小说而是五本英语小说。(not… but) 10. 他是否已被那所大学录取令他的父母很担心。(whether) 11. 不久我们就要参观那座博物馆了。(before) 2. 尽管有很多困难，我们仍将执行我们的计划。(carry) 13. 当我们听到中国将主办2008年奥运会的消息，我高兴得跳了起来。(learn) 14. 政府向遭受水灾的人们提供药品和食品。(provide) 15. 据报道这个国家三分之一的城市缺水。(short) 16. 这两家公司的贸易谈判中断了，以至于经理们不得不寻找其他的合作伙伴。(between) 17. 电子邮件同电话一样，在日常交流中起着重要作用。(as well as) 18. 学生们向老师解释玛丽缺课的原因是她患了感冒。(reason) 19. 如果你不是昨晚熬夜的话，你现在就不会打瞌睡了。(sleepy) 20. 应该采取行动来阻止黑客侵犯我们的电脑系统。(prevent) 参考答案： 1.Our monitor is regarded as the best student in our class. 2.The development of modern science and technology has brought about great changes to our society. 3.You can’t learn English well without practicing speaking English. 4.Everyone should know how to obey the traffic rules, and thus many traffic accidents can be avoided. 5.I have come to realize that one can’t learn a foreign language well unless he works hard. 6.You should concentrate on your lessons in class, otherwise you can’t understand what the teacher has said. 7.He broke his neighbour’s windows again, which made his parents very angry. 8.Good health depends on good food, exercise and enough sleep. 9.Within that term he read not one English novel but five. 10.Whether he had been admitted to that university or not worried his parents. 11.It won’t be long before we visit that museum. 12. In spite of many difficulties, we’ll still carry out our plan through to the end. 13. On hearing the news that 2008 Olympic Games would be held in China, I jumped up because of joy. 14. The government provided medicine and food supplies for the people in the area affected by flood. 15. It is reported that one-third of the cities in the country are short of water supply. 16. The trade talks between the two companies broken down so that their managers had to look for another trade partner. 17. E-mail, as well as telephones, is playing an important part in daily communication. 18. The reason that the students explained to the teacher for Mary’s absence was that she was down with flu. 19. If you hadn’t stayed late last night, you wouldn’t be so sleepy now. 20. Action should be taken to prevent hackers from breaking into our computer system.