运转中的发电机在（）故障时停机。
A、油压低
B、水温低
C、转速高
D、电压异常
参考答案：A, C, D
It was ______ the president's speech that the secretary spent the whole morning at home.
A．to prepare
B．preparing
C．prepared
D．be prepared
XY一2型钻机离合器结合时，杠杆力端与轴承平面应保持（）mm的间隙。
A．0.3
B．0.5
C．0.8
