2. (07郑州一质测)We should all remember that some great scientific discoveries_____ by chance.

A. occurred　　　　　　　 B. were occurred　　　　　　　　　　 C. have occurred　　　　　 D. had been occurred

1.(07郑州一质测)It is the first time that he ______ to join us in a research.

A. agree　　　 　　　 　B. agreed　　　　 　 C. has agreed　　　　　　　　 D. will agree

31. (’06辽宁，31) It is said that the early European playing-cards ________ for entertainment and education.

A. were being designed　 　　　 B. have designed　 　　　 　C. have been designed　 　 D. were designed

考能提升训练

30. (’06辽宁，29) I think it is necessary for my 19-year-old son to have his own mobile, for I sometimes want to make sure if he _____ home for dinner.

A. come　 　　　　　　　　　 　B. comes　　 　　 　C. has come　 　D. will come

29. (’06辽宁，27) The father as well as his three children ________ skating on the frozen river every Sunday afternoon in winter.

A. is going　 　　　　　　　　 　B. go　 　 　C. goes　　 　　　 　D. are going

28. (’06山东，28) Although the causes of cancer_______, we do not yet have any practical way to prevent it.

A. are being uncovered　 　　　 B. have been uncovering　　 C. are uncovering　 　　　　　　　 D. have uncovered

27. (06陕西，12) The construction of the two new railway lines ______by now.

A. has completed　　 　 B. have completed　　 C. have been completed　　 　　　 D. has been completed

26. (’06陕西，7)---- You look very tired. _____ at all last might?

----No, not really. I’m tired out now.

A. Do you sleep　　　 B. Were you sleeping　　　 C. Did you sleep　　　 D. Had you slept

25. (’06江苏，23) ----I don’t suppose the police know who did it.

---- Well, surprisingly they do. A man has been arrested and _______now.

A. has been questioned　　　　　 B. is being questioned　　　　　　 C. is questioning　　 D. has questioned

24. (’06安徽，25)　 I ______ along the street looking for a place to park when the accident_________.

A. went; was occurring　　 B. went; occurred　　　 C. was going; occurred　　　 D. was going; had occurred