An inflatable liferaft can be launched by（）.

A.the float-free method ONLY

B.breaking the weak link on the painter

C.throwing the entire container overboard and then pulling on the operating cord to inflate the raft

D.removing the securing straps

甲醇合成单元停电停车，操作上首先是（）。

A、开汽包上水调节阀

B、切除原料气

C、关汽包副产蒸汽压力调节阀

D、关汽包排污阀