71._______ for your laziness，you could have finished the assignment by now.

　　A. Had it not been B. It were not C. Weren‘t it D. Had not it been

　　72.The new discovery _______ be of great service to mankind.

　　A. is bound to B. is bound for C. be bound to D. be bound for

　　73.Sickness often _______ eating too much.

　　A. as a result of B. result of C. result in D. result from

　　74.It took me a month to get rid _______ the cough.

　　A. for B. as C. of D. over

　　75.They are eager _______ abroad.

　　A. travel B. travelled C. to travel D. travelling

　　76.I would love ________ to the party last night but I had to work extra hours to finish a report.

　　A. to go B. to have gone C. going D. having gone

　　77.________ in thought， he almost ran into the car in front of him.

　　A. Losing B. Having lost C. Lost D. To lose

　　78.—You were brave enough to raise objections at the meeting.

　　—Well， now I regret ________ that.

　　A. to do B. to be doing C. to have done D. having done

　　79.The missing boys were last seen ________ near the river.

　　A. playing B. played C. play D. to play

　　80.The visiting minister expressed his satisfaction with the talks， ________ that he had enjoyed his stay here.

　　A. having added B. to add C. adding D. added