单项选择题
When an auxiliary boiler is panting and emitting black smoke, you should （）.
A.increase the fuel oil temperature B.decrease the fuel oil temperature C.decrease the fuel oil supply pressure D.increase the air supply
单项选择题 Close the （）.
单项选择题 Which pump is the self-priming pump?（）
单项选择题 The younger motorman as well as the others （） to operate the oil separator.
