单项选择题
A.non-synchronous electric motor
B.synchronous electric motor
C.fully enclosed electric motor
D.watertight electric motor
单项选择题 Which of the following statements is not true concerning symptom of a fire in the scavenge air box?()
单项选择题 Which of following functions is not one of the functions of air conditioner?()
单项选择题 The oil discharge monitoring system in the oil tanker vessels is used for detecting the amount of oil discharged overboard to ensure that it does not exceed()