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【单选题】
( )机构用于举起重物或克服大的生产阻力，如螺旋千斤顶、螺旋压力机、台虎钳等。
A.
传导螺旋
B.
调整螺旋
C.
传动螺旋
D.
测量螺旋
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【判断题】作变速稳定运动的机器，设在某一瞬时，同样的驱动力F，在实际情况下和理想情况下所能克服的生产阻力分别为、，则该机器的瞬时效率为 A. ； B. ； C. 。A. 错误B. 错误C. 正确D. 错误
A.
正确
B.
错误
【单选题】In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horses, and carts got stuck. An old joke that was popular at the time went somet...
A.
horses were fairly useful in Chicago
B.
Chicago"s streets were extremely muddy
C.
Chicago was very dangerous in the spring
D.
the Chicago people were particularly humorous