79. I don't think he could have done such a stupid thing last night, ______?

　　 A. do I　　　　 B. could he　　　 C. did he　　　　 D. has he

78. The death of the dog made her sad, and it took a long time to _____it.

　　 A. put off　　　　 B. get down　　　 C. get over　　　　 D. come across

77. ______ your business becomes international, ______constantly will be part of your life.

A. For; flying　　　　 B. Since; flight　　　 C. Now that; flight　　　 D. Once; flying

76. I've listened to Dr Johnson's talk about pollution, but I still haven't a good understanding of its key ______.

　　 A. words　　　 B. points　　　 C. information　　 　D. notes

75. --Do you still remember the day when we went to the Great Wall7

　 --I can't remember it well, but _______ sometime last autumn?

　　 A. might it be　　　　　　　　　　 B. must it have been

　　 C. could it have been　　　　　　 　D. could it be

74. Mrs Black is expecting another baby and hopes ______ will be a boy.

　　 A. he　　　　　 B. that　　　　　 C. it　　　　　　 D. who

73. --Did you have trouble finding the house?

　 --______.

　　 A. No, completely none　　　　　 　B. Yes, completely none

　　 C. No, hardly one　　　　　　　　 D. Yes, I've got one

72. Enough of it! Nobody here thinks what you're saying should make any ______.

　　 A. excuse　　　 B. sense　　　　　 C. use　　　　　 D. value

71. My son _____ his English composition last night, now he's continuing it.

　　 A. wrote　　　　　 B. was writing　　　 C. had written　　　　 D. has written

70. --It was careless of you ______ your bike unlocked outside all night.

　 --My God! So I did.

　　 A. to leave　　 　　B. left　　　 C. had left　　　　 D. to have left