油的粘度随温度变化，直接影响运动速度，故液压系统不宜在高、低温的环境中工作。
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在经济处于全面均衡状态时，某种商品的供给量的增加将导致其替代品市场价格上升。
A. 正确
B. 错误
While inspecting the main bearings on a diesel engine you find impregnated dirt and scratches in the bearing surface you would, therefore, suspect that （）
A. the bearing had been overheated
B. water was present in the oil
C. the lube oil was not being properly filtered
D. the maximum allowable bearing pressure had been exceeded
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