3．若为等差数列，是其前项和，且，则的值为　　　　　　 (　　 )

　　　 A．　　　　　　　　 B．　　　　　　　　　　 C．　　　　　　　　　 D．

2．已知集合为实数集，集合则等于

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 (　　 )

　　　 A．　　 B．　　 C．　　　　　 D．

1．的值为　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 (　　 )

　　　 A．　　　　　 B．　　　　　 C．　　　　　　　　　 D．

26. It is not what you say is right but what you do _______ is of importance.

A. which　　　　　　 B. it　 　　 C. that 　 　　　 　D. this

25.-Has Sam finished his homework today?

-I have no idea. He ________ it this morning.

　 A. did　　 B. has done　 C. was doing　 D. had done

24.-People should be encouraged to use public transport instead of cars.

-__________. The roads are really too crowded.

A. All right　　　 B. No problem　　 C. Go ahead　　 　D. Exactly

22. Don’t you know that your school is, as a matter of fact, ______ used to be a church? A. where　　 　B. what 　　　C. that 　　　D. which 23.-How long do you suppose it is______ he arrived here? 　 -No more than half a week. A. since 　　B. before　 　C. after 　　　D. when

21. Not until his parents turned off the TV, _________________.

A. did he go to bed　　　 B. didn’t he go to bed

C. he did go to bed 　　　D. he didn’t go to bed

20. To our great______, Mary’s illness proved not to be as serious as we had feared.

A. anxiety　 　B. relief 　　C. view　　 D. judgment