单项选择题
A.many thousand times B.between times C.one time D.at times
Here some oil in the oily water separator, as a result ...
单项选择题Here some oil in the oily water separator, as a result of its lower （）, will separate and rise into the oil collection space.
A.temperature B.viscosity C.density D.velocity
Heat energy is a source of power, but （） will cause dam...
单项选择题Heat energy is a source of power, but （） will cause damage to the engine.
A.excessive heat B.insufficient heat C.effective cooling D.high output
Head tank should be used to remove （） from cooling wate...
单项选择题Head tank should be used to remove （） from cooling water.
A.scale B.sludge C.chemicals D.air
