51. Yesterday he sold out all his stamps at ____ he thought was a reasonable price.

　　A. that B. which C. what D. as

　　52. Generally speaking, ____ we have seen seems more believable than ____ we have been told.

　　A. what; that B. what; what C. that; what D. that; that

　　53. After three days’ waiting, there was a little doubt in the mother’s mind ____ the police could find her lost child.

　　A. how B. that C. where D. whether

　　54. “Sustainable development” is a question ____ we can continue developing the world without damaging the environment.

　　A. whether B. when C. that D. how

　　55. We’d like to do ____ we can ____ the poor.

　　A. how; help B. all; to help C. whatever; help D. however; to help

　　56. Your cell pone is always being power off. ____ we got through, we wouldn’t have to come to your home now.

　　A. If B. Once C. Had D. Should

　　57. _____ the comedy has brought us!

　　A. How great fun B. What great fun C. How a great fun D. What a great fun

　　58. How cold your hands _____!

　　A. felt B. are felt C. feel D. are feeling

　　59. It is one thing to write a novel , ____.

　　A. the other to write history B. another to write history

　　C. the other is to write history D. another is to write history

　　60. ---Why not go out for a picnic on such a sunny day?

　　---____ like a good idea.

　　A. Sounding B. Sounds C. Sounded D. Sound

　　61. Errors, if ____, should be corrected.

　　A. necessary B. possible C. any D. important

　　62. Today everyone arrived earlier than ____.

　　A. expecting B. having expecting C. to be expect D. expected

　　63. ---What do you suppose has made Carrie so upset?

　　---____ her new sell phone.

　　A. Because of having lost B. Because she lost C. Lost D. Losing

　　64. Don’t cry any more, Tony. Or I’ll regret ____ the truth.

　　A. to tell you B. to have told you C. to telling you D. telling you

　　65. Every one has his or her right to object ____ unequally.

　　A. to treat B. to treating C. to be treated D. to being treated

　　66. When I passed by, she pretended ____ me.

　　A. to don’t recognize B. not recognizing

　　C. to have not recognized D. not to have recognized

　　67. He is such a man who is difficult ____.

　　A. to satisfy with B. to be satisfied with C. to satisfy D. to be satisfied

　　68. Have you seen the man ____ on the grass in the picture?

　　A. lay B. lain C. laying D. lying

　　69. All the guests ____ to the party were enjoying themselves.

　　A. to be invited B. having invited C. invited D. being invited