液压系统工作时油箱内的油温不得超过（）℃。
A．40
B．50
C．60
D．80
参考答案：C
--- Would you mind speaking more slowly. I can hardly ________ you.
---_________________.
A．read, Of course
B．follow, Of course not
C．miss, Ok
D．match, Good idea.
格栅荧光灯灯具的效率应不低于( )。
A．75% B．65% C．60% D．55%
