单项选择题
A.well B.good C.excellent D.respectively
It is necessary to remove （） from the cooling water spa...
单项选择题It is necessary to remove （） from the cooling water spaces to improve heat transfer.
A.lime B.frost C.scale D.scar
It is necessary to remove （） from the cooling spaces.A....
单项选择题It is necessary to remove （） from the cooling spaces.
A.scar B.scale C.spur D.bilge
It is necessary to （） cool the various components of th...
单项选择题It is necessary to （） cool the various components of the machinery so that the engine can work properly.
A.continuously B.regularly C.constantly D.period
