五道英语题,望能说明原因?

题目

五道英语题,望能说明原因?
21. The 2010 Shanghai World Expo is intended to achieve our common goal: ________world that is safer, cleaner and healthier than ________ one we’re liv ing in.A. the; the                 B. a; /                C. a ; the                  D. the ; /   28. --- Did you often e-mail your family during the first year at university?   --- No. I was so busy meeting new people that I didn’t write to my family as I _____.    A. ought to           B. should do             C. should have written   D. should have30. Mr. Fox fell ill, thus __________ it necessary for us to find another person for his job.A. having mad

答案

21.C 2010上海世博会是为了达成我们的共同目标：一个比我们现在居住的世界更安全,更干净,更健康的世界.(第一空是指一个新的世界 第二空是特指我们现在居住的世界 所以应该加上定冠词the)28.C -你在你大学第一年经常...