目前采煤防滑装置有（）、抱闸式、防滑安全绞车等防滑装置。
A.防滑杆
B.防滑顶子
C.防滑链
D.防滑制动
参考答案：A
Police are searching for an escaped criminal who is reported to _____ since he broke away from the prison．
A．have been missing
B．have lost
C．be missing
D．get lost
在出铁的全过程中，铁口的孔径是不变。
