单项选择题
When air is at its dew point it（）.
A.will contain no additional moisture B.has the lowest relative humidity C.cannot keep up its moisture D.has a low absolute humidity
单项选择题 When cargo is shifted from the main deck into the lower hold of a vessel,（）.
单项选择题 When liquid is free to move transversely in a tank, the effect is called（）.
单项选择题 When the truck does not work, the driver should（）engines.
