Before starting a reciprocating steam-driven pump that has been idle for a period of time

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Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should _____.

A.open the steam line mot valve

B.drain the steam cylinder

C.close the steam cylinder drains

D.open the liquid cylinder drains

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热搜:a是b的充分条件,b是a的必要条件吗