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问题 单项选择题

选用起重能力大于起重物的千斤顶，几台联用时，每台的起重能力不得小于其分担荷载的（）。

A、1～1.2倍

B、1.2～1.5倍

C、1.5～2.0倍

D、2.0～2.5倍

答案

参考答案：B

单项选择题

现金库房的两把使用钥匙应实行（）

A、一人保管

B、交叉传递

C、单线传递

D、营业时入箱保管
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单项选择题

In the following essay, each blank has four choices. Choose the best answer and writedown on the answer sheet.

Microwave communication uses high-frequency (26) waves that travel in straightlines through the air. Because the waves cannot (27) with the curvature of the earth, they can be (28) only over short distance. Thus, microwave is a good (29) for sendingdata between buildings in a city or on a large college campus. For longer distances, the wavesmust be relayed by means of "dishes" or (30) . These can be installed on towers, highbuildings, and mountain tops.

（30）是（）

A.repeaters

B.radars

C.telephones

D.antennas
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