We don’t allow ___in the office. But you are allowed ____in the rest room.

A．smoking, smoking

B．to smoke, to smoke

C．smoking, to smoke

D．smoke, smoking

倾斜井巷跑车事故危害极大，基主要原因一般有（）、制动装置不良和操作失误。

A、钢丝绳断裂

B、连接件断裂

C、矿车底盘钢断裂

D、连接销窜出脱钩