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單項(xiàng)選擇題

In the closed cooling system, the water （）.

A.is made to circulate out of the system
B.is made to circulate within the system
C.is made circulate within the system
D.is made circulate out of the system

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單項(xiàng)選擇題

If the temperature drops low enough, oil will not flow, （） just tell us the temperature.

A.Hash point
B.Viscosity
C.Pour point
D.Cetane number

單項(xiàng)選擇題

The （） can tell us how much heat we can get from the burning of an oil.

A.viscosity
B.flash point
C.cetane number
D.calorific value