单项选择题
A.Distance a wave travels between formation and decay B.Stretch of water over which a wave-forming wind blows C.Time in seconds required for two crests to pass a given point D.Measurement of a wave's steepness
Cyclones that have warm sectors usually move（）.A.wester...
单项选择题Cyclones that have warm sectors usually move（）.
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
