电动机运行的基本要求是，当冷却空气温度t高于35℃时，电动机的功率应较额定功率降低( )。

A．(55-t)%

B．(45-t)%

C．(35-t)%

D．(25-t)%

Before we started out, we'd better()the time of the next train in the time table.

A．look after

B．look for

C．look up

D．to look for