单项选择题

When preparing an engine for water temperature（）

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℃

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热门试题

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

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

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

单项选择题The closed-loop system differs from the open-loop system by（）

A.the lack of a feedback
B.the presence of a feed back
C.the lack of a computer
D.the presence of a computer

单项选择题From the passage, we can learn that the simplest controller action is（）

A.two-step controller action
B.proportional, controller action
C.integral controller action
D.derivative controller action