单项选择题
A.should be kept at a proper level by a cooler B.should be raised to about 80℃ by a heater C.should be raised gradually D.should be lowered to about 60℃
When stand-by engine instructions have been received, i...
单项选择题When stand-by engine instructions have been received, it’s necessary to make it sure that all valves in the various systems are（）
A.operational B.open C.closed securely D.at middle position
The monitoring function may serve all of the following ...
单项选择题The monitoring function may serve all of the following purposes except（）
A.instigating corrective action B.indicating values of controlled variables C.warning of off-limit conditions D.providing record of performance
A feedback is an input（）A.which governs the state of a ...
单项选择题A feedback is an input（）
A.which governs the state of a variable B.which provides a visual and audible alarm C.which indicates values of controlled variables D.which measures the state of the controlled variable
