单项选择题
A.Cirrostratus B.Cirrus C.Cirrocmulus D.Altostratus
（）are mainly caused by the gravitational pull of the mo...
单项选择题（）are mainly caused by the gravitational pull of the moon.
A.Tides B.Sea C.Swell D.Wind
（）generally indicates that a gale or storm is approachi...
单项选择题（）generally indicates that a gale or storm is approaching.
A.Falling barometric pressure B.Rising barometric pressure C.The circulations of winds D.The change of wind direction
（）indicates unstable weather.A.The persence of cirrus c...
单项选择题（）indicates unstable weather.
A.The persence of cirrus clouds B.The low-hanging stratus clouds C.The altocumulus clouds D.The massive cumulus clouds
