船舶的推进器效率的通常值为:()
A.0.95~0.98
B.0.80~0.95
C.0.60~0.75
D.0.50~0.70
参考答案:C
—Hi, Jim, ____ you come to my party?
—Sorry, I can't. I have to do my homework. [ ]
A. can
B. may
C. need
D. must
蒸汽吹扫控制阀时,应将()。
A、控制阀改走副线
B、将控制阀全开
C、关闭控制阀,开低点排凝
D、关闭控制阀上游阀,从下游开蒸汽吹