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问题 单项选择题

用锤击沉桩时，为了防止桩受冲击应力过大而损坏，其锤击方式应是（）

A.轻锤重击

B.轻锤轻击

C.重锤轻击

D.重锤重击

答案

参考答案：C

解析：当锤击沉桩时，桩锤轻质量小难以使桩下沉，重锤重击桩又因受冲击应力过大而易损坏，一般以采用重锤轻击为宜。

选择题

钱学森在美国期间，在他撰写的一篇文章封面先是写上“Final”(最后的定稿)，后来又在旁边添加了“Nothing is final！”(没有什么认识是最后的)。他之所以这样做，是因为 (　　)

①真理是具体的，有条件的　             ②认识具有反复性和无限性　

③随着实践的发展，已经确定的真理会被推翻④真理是标志主观同客观相符合的哲学范畴

A．①②

B．①③

C．②④

D．③④
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单项选择题

Visitors to this country are normally admitted for six months, but foreign students can usually stay for one year. They must (52) an educational institution, and they are required to study for a (53) of fifteen hours a week on a daytime course. Prospective students have to show that they can afford their studies, and that they have sufficient (54) resources to support themselves (55) in this country.

In order to work here the foreigner needs a work permit, (56) must be applied for by his prospective employer. The problem here is that the Department of Employment has the right to grant or (57) these permits, and there is little that can be done (58) it; it would be extremely unwise for a foreign visitor to work (59) a permit, since anyone doing so is liable to immediate deportation (驱逐出境). There are some people from the European countries, who are often given (60) residence permits of up to five years. Some other people, such as doctors, foreign journalists, authors and others can work without permits, and foreign students are normally allowed to (61) part-time jobs while they are studying here.

52().

A.minimum 

B.maximum 

C.minority 

D.majority
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