单项选择题
A.tornado B.anticyclone C.occluded cyclone or occluded front D.polar cyclone
A cloud sequence of cirrus，cirrostratus，and altostratus...
单项选择题A cloud sequence of cirrus，cirrostratus，and altostratus clouds followed by rain usually signifies the approach of a(n)（）.
A.occluded front B.stationary front C.warm front D.cold front
A cloud of marked vertical development (often anvil-sha...
单项选择题A cloud of marked vertical development (often anvil-shaped) would be classified as（）.
A.cirrus B.cirrocumulus C.altocumulus D.cumulonimbus
A boundary between two air masses is a(n)（）.A.lapse rat...
单项选择题A boundary between two air masses is a(n)（）.
A.lapse rate B.isobar C.front D.continent
