28. Although the causes of cancer _______, we do not yet have any practical way to prevent it. (2006山东卷)

A. are being uncovered                    B. have been uncovering   

C. are uncovering                              D. have uncovered

【答案】A。

【考点】考查动词的被动语态。

【解析】“癌症的原因”应该是“被”揭开，故应用被动语态; 另外，从句意上看，此处应用现在进行时。

29. Five people won the “China’s Green Figure” award, a title _______ to ordinary people for their contributions to environmental protection. (2006山东卷)

A. being given     B. is given             C. given                 D. was given

【答案】C。

【考点】考查非谓语动词用法。

【解析】由于title与give之间为被动关系，故用过去分词。

30. —May I smoke here?

—If you _______, choose a seat in the smoking section. (2006山东卷)

A. should             B. could                 C. may                   D. must

【答案】D。

【考点】考查情态动词辨析与用法。

【解析】must在此表示坚持或固执，又如：After I gave her my advice，she must go and do the opposite. 在我给她出主意之后她偏反着干。

31. How can you expect to learn anything _______ you never listen? (2006山东卷)

A. in case             B. even if               C. unless              D. when

【答案】D。

【考点】考查状语从句。

【解析】when在此表示“既然”，又如：How can they learn anything when they spend all their spare time watching television? 他们把所有的空闲时间都用来看电视了，还能学什么东西呢?

32. I just wonder _______ that makes him so excited. (2006山东卷)

A. why it does      B. what he does   C. how it is            D. what it is

【答案】D。

【考点】考查宾语从句的连接词及强调句。

【解析】本题干相当于I just wonder what makes him so excited.的意义，所以该题实际上为强调句型的特殊疑问句式，what为宾语从句的连接词且在从句中做主语，句意为：我想知道什么使得他如此兴奋。

33. Police are now searching for a woman who is reported to _______ since the flood hit the area last Friday. (2006山东卷)

A. have been missing                       B. have got lost    C. be missing       D. get lost

【答案】A。

【考点】考查非谓语动词用法。

【解析】根据句中的since可知，此处应用完成式，故可排除C和D。根据句意，missing(不见，失踪)比用lost(丢失，迷失)更合适。

34. After he retired from office, Rogers _______ painting for a while, but soon lost interest. (2006山东卷)

A. took up            B. saved up          C. kept up             D. drew up

【答案】A。

【考点】考查短语动词辨析与用法。

【解析】take up 在此表示“开始(学习或从事等)”。如：He dropped medicine and took up physics. 他放弃学医，开始学物理。For a long time I had wanted to take up writing. 很久以来我一直想从事写作。

35. A clean environment can help the city bid for the Olympics, which _______ will promote its economic development. (2006山东卷)

A. in nature          B. in return            C. in turn               D. in fact

【答案】B(//www.julie-photo.com/)。

【考点】考查介词短语辨析。

【解析】in nature 意为“本质上”“事实上”; in return 意为“作为报答”; in turn 意为“依次”; in fact意为“事实上”。根据句意，显然只有B最恰当。