HD型刀开关与DW型断路器串联使用时，拉闸顺序是（）。
A.先DW，后HD；
B.同时拉；
C.先HD，后DW；
D.先拉哪个都行。
参考答案：A
Mrs．Smith gave us some _______ on how to learn English well． [ ]
A．prize
B．notice
C．advice
D．news
The number of people invited to the wedding yesterday ______ two hundred, but a small
number of them ________ absent .
A．is ; are
B．was ; was
C．was ; were
D．are ; were
