（）接触器是用来频繁地遥控接通或断开交直流主电路及大容量控制电路的自动接触器，还具有欠电压，零电压保护，操作频率高，工作可靠，性能稳定，维护方便，寿命长等优点。

（） mechanical device has ever been invented that can satisfactorily replace teasel flower heads for raising the nap on cloth.

A．No

B．Not the

C．Never has a

D．There is no