Catherine bought a postcard of the place she was visiting, addressed______to _____and then posted it at the nearby post office．

A．it; her

B．it; herself

C．herself; her

D．herself; herself

在低压供电系统中用来整定保护装置灵敏度的电量为（）。

A.系统最小运行方式下单相短路电流

B.系统最大运行方式下单相短路电流

C.系统最大运行方式下二相短路电流

D.系统最小运行方式下二相短路电流