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问题 单项选择题

按照钢丝绳的容许拉力经验公式S容=10d绳2（kgf）计算，一根直径24mm的钢丝绳的容许拉力为（）。绳直径单位为毫米。此经验公式算出的容许拉力其钢丝绳安全系数为5。

A.5760kgf

B.39200kgf

C.5760N

D.1568kgf

答案

参考答案：A

单项选择题

由腕骨、掌骨及指骨构成手的纵弓关键点在（）

A.掌指关节

B.指间关节

C.远侧指间关节

D.近侧指间关节

E.腕关节
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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 (51) an educational institution, and they are required to study for a minimum of fifteen hours a week on a (52) course. Prospective students have to show that they can afford their studies, and that they have sufficient (53) resources to support themselves (54) in this country.

In order to work here the foreigner needs a work permit, (55) must be applied for by his prospective employer. The problem here is that the Department of Employment has the right to grant or (56) these permits, and there is little that can be done (57) it; it would be extremely unwise for a foreign visitor to work (58) a permit, since anyone doing so is liable to immediate deportation (驱逐出境). There are some people from the Common Market countries, who are often given (59) 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 (60) part-time jobs while they are studying here.

55().

A.when 

B.what 

C.where 

D.which
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