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【单选题】

局部通风机产生较大震动的原因()

A.
轴承磨损
B.
温度过低
C.
叶轮不平衡
D.
润滑不良
举报
参考答案:
参考解析:
.
刷刷题刷刷变学霸
举一反三

【单选题】轴流式通风机主要利用()进行反风。

A.
调节叶片安装角
B.
风机反转
C.
反风道
D.
都可以

【单选题】The Grand Canyon Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant wound in the Earth’’s surface, a visitor might assume that the canyon had been caused by some ancient convulsion...

A.
it was caused by some ancient convulsion
B.
its presence is an embarrassment to the state of Colorado
C.
it looks like an injury on the Earth’s surface
D.
it has caused many visitors to injure themselves