单项选择题
A.westerly B.parallel to the isobars in the warm sector C.toward the nearest high pressure area D.faster than the accompanying cold front
Cumulus clouds that have undergone vertical development...
单项选择题Cumulus clouds that have undergone vertical development and have become cumulonimbus in form，indicate（）.
A.clearing weather B.that a warm front has passed C.probable thunderstorm activity D.an approaching hurricane or typhoon
Cumulonimbus clouds are formed by（）.A.vertical air move...
单项选择题Cumulonimbus clouds are formed by（）.
A.vertical air movements B.heavy rainstorms C.horizontal air movements D.any movement of moist air
Corrosive liquids and acids should have which kind of l...
单项选择题Corrosive liquids and acids should have which kind of label?（）
A.Skull and crossbones B.Yellow and white C.Red and white D.White and black
