35. ---Jack, how did it ______ that you made so many mistakes in your homework?

　　 ---I myself haven't figured it out yet.

　　 A. occur to　　　 B. come about　　　　　　 C. bring about　　　　　 D. get down

34. ---I feel the house shaking.

　　 ---So do I. It ______ be a sign of an earthquake most probably. Let's hurry to leave here.

　　 A.must　　　　　　 B.　 ought to　　　　　　 C. can　　　　　　　 D. might

33. ---Tom, did Mr. Alex join in your discussion?

　　 ---No, he ______, but he happened to have fallen ill.

　　 A. would like to　　 B. was to have　　 C. will　　　 　　D. was going to join

32. ---The weather isn't good enough for an outing, is it?

　　 ---Not in the least. We can't have ______ at this time of the year.

　　 A. a nicer day　　 B.　 a worse day　　　 C. a worst day　　　　 D. so fine a day