The passing of a low pressure system can be determined by periodically checking the（）.

单项选择题The moisture equilibrium chart can be used to determine the（）.

A.Absolute moisture content of the air surrounding a hygroscopic cargo when moisture equilibrium exists
B.Dew point temperature that the air surrounding a hygroscopic commodity will have when in moisture equilibrium with that commodity
C.Enthalpy of the air surrounding a hydroscopic cargo which is in moisture equilibrium with the cargo
D.Temperature at which moisture equilibrium will occur in a cargo hold containing a hygroscopic cargo

单项选择题The force resulting from the earth’s rotation that causes winds to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere is called（）.

A.Pressure gradient
B.Coriolis effect
C.Aurora borealis
D.Ballistic deflection

单项选择题The doldrums are characterized by（）.

A.Steady，light to moderate winds
B.Frequent calms
C.Clear skies
D.Low humidity

单项选择题The direction of prevailing winds in the Northern hemisphere is caused by the（）.

A.Magnetic field at the North Pole
B.Gulf Stream
C.Earth's rotation
D.Arctic cold fronts

单项选择题Steady precipitation is typical of（）．

A.Coming cold weather conditions
B.A warm front weather condition
C.High pressure conditions
D.Scattered cumulus cloudsduring the day