单项选择题
A.becomes slack
B.can not be paid out unless the brake is overhauled or recover wire unless manually operated
C.will be let out because the brake is out of work
D.may be pay out due to no power
单项选择题 For a flash type evaporator, a demister is located the condenser（）
单项选择题 For a flash type evaporator, the seawater heater will have to maintain a enough temperature to minimize scale formation（）
单项选择题 The flash-evaporator is different with the submerged-tube evaporator in that for the former（）