单项选择题
A.with both pumps on line at the same time
B.with one pump on standby
C.with the follow-up gear disconnected
D.only when the rudder is moved amidships
单项选择题 One distinct advantage of flash type evaporators, as compared to most other evaporators, is that in a flash evaporator （）.
单项选择题 A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently chargedIt is generally located in the（）.
单项选择题 Compared to a constant pitch propeller, a controllable pitch propeller（）.