50. As a natural body substance, interferon (干扰素) has few side _____.
A) influences
B) effects
C) impacts
D) functions
51. The police _____ together all they had found out about the wanted man.
A) combined
B) mixed
C) pieced
D) joined
52. When Bob came in, Jean _____ her talk with Linda and talked to Bob.
A) broke off
B) cleared away
C) cut across
D) set apart
53. Foreign mutton is _____ to home-grown in flavor.
A) worse
B) indifferent
C) inferior
D) subordinate
54. I _____ work last week, but I changed my mind.
A) were to start
B) was to start
C) was to have started
D) had started
55. The children went there to watch the iron tower _____.
A) to erect
B) be erected
C) erecting
D) being erected
56. After the Arab states won independence, great emphasis was laid on expanding education, with girls as well as boys _____ to go to school.
A) to be encouraged
B) been encouraged
C) being encouraged
D) be encouraged
57. _____ such a good chance, he planned to learn more.
A) To be given
B) Having been given
C) Having given
D) Giving
58. —— Has Mary finished writing his article? —— No, and it _____ two days ago.
A) should be finished
B) should finish
C) should have finished
D) ought to have been finished
59. I had better _____ the problem.
A) leave them to settle
B) to leave them to settle
C) to leave them settling
D) leave them settling
60. _____ it is necessary to study the proposals for several more months before making a decision is to be debated.
A) Whether
B) If
C) What