46. When he arrived， he found _C_ the aged and the sick at home.
A nothing but B none other C none but D no other than
形容词前加the表示一类人。 none but 只有，仅有。
47. The pressure _B_ causes Americans to be energetic， but it also puts them under a constant emotional strain.
A competing B to compete C to be competed D having competed
the right to vote 选举权。 动词不定式作后置定语要用主动形式。
the pressure to compete 竞争的压力。
48. It s no use _B_ me not to worry.
A you tell B your telling C for you to have told D having told
It s no use + 动名词。 动名词的复合结构，宾格+ 动名词。
49. As teachers we should concern ourselves with what is said， not what we think _C_.
A have to be said B must say C ought to be said D need to say
50. Once environmental damage _A_， it takes many years for the system to recover.
A is done B is to do C does D has done
51. Studies show that the things that contribute most to a sense of happiness cannot be bought， _B_ a good family life， friendship and work satisfaction.
A as for B such as C in case of D in view of
contribute to 对 做出贡献。
52. He will agree to do what you require _D_ him.
A for B from C to D of
require sth. of sb. 要求某人做某事。
53. The mere fact _A_ most people believe nuclear war would be madness does not mean that it will not occur.
A that B which C what D why
fact后面要加同位语从句。
54. John seems nice person. _C_， I don t trust him.
A Even though B Therefore C Even so D Though
even so 即便如此，尽管如此。
55. I don t think it advisable that Tom _A_ to the job since he has no experience.
A be assigned B will be assigned C is assigned D has been assigned
advisable后面加句子要用虚拟语气，形式为：+ 动词原形。