用指针式万用表测量桥式整流电路的输出电压时，黑表笔应接整流管的负极。
参考答案：对
我国临海的省级行政单位共有[ ]
A．11个
B．12个
C．13个
D．14个
– A number of students ____ in the dinning hall.
-- Let me count. The number of the students ____ about 400.
A．are, is
B．is, are
C．are, are
D．is, is
