31.－Why didn’t you answer when I called you?

　 －I_____but you didn’t hear me.

　　　 A.had to　　 B.couldn’t　　 C.didn’t answer　　 D.did

30.Where is my pen? I_____it.　　

　 A.should have lost　　 B.must have lost　　 C.would have lost　　 D.might lose

29.－Shall I tell John about it?

　 －No,you_________.I’ve told him already.　

　　　 A.needn’t　　　　 B.wouldn’t　　　　 C.mustn’t　　　　 D.shoudn’t

28.－Can I help you,sir?

　 －Yes,I bought this radio here yesterday,but it______.

　　　 A.didn’t work　　 B.couldn’t work　　’t work　　 D.doesn’t work

27.I told Sally how to get here,but perhaps I________for her.

　　　 A.had to write it out　　　　　　 B.must have written it out

　　　 C.should have written it out　　 D.ought to write it out　　

26. He is a teacher but his wife is a doctor,_______?

　　 A.isn’t she　　 B.isn’t it　　 C.aren’t they　　 D.isn’t he

25.More than one person_____involved in th case.

　　 A.is　　 B.are　　 C.has　　 D.have

24. Each soldier and sailor_____given a rifle when the ship landed.

　　 A.were　　 B.was　　 C.are　　 D.is

23. No one has finished his homework,________?

　　 A.have they　　 B.haven’t they　　 C.has he　　 D.hasn’t he

22．_____either he or I to leave for America?

　　　 A. Is　　 B.Am　　 C.Are　　 D.Will