当按钮放开时，可依靠（）把动触点复归到原来的位置。
A、电磁铁；
B、复位弹簧；
C、电压。
参考答案：B
补全对话
A: Excuse me, sir, 1 hotel?
B: I am sorry I don't. You may ask that policeman over there.
A: Thank you 2 .
A: Excuse me. 3 ?
C: No, there isn't a hotel near here. But there is one near the Bank of China.
A: 4 .
C: It's about two kilometers away.
A: 5
C: You'd better take a taxi, because it's so late, there aren't any buses now.
A: 6 .
C: You're welcome.
( )是指在社会经济正常的情况下，由自然力的不规则变化或人们的过失行为所致损失或损害的风险。
A．动态风险
B．自然风险
C．纯粹风险
D．静态风险
etter take a taxi, because it's so late, there aren't any buses now.