单项选择题
A.one zone to the east B.one zone to the west C.two zones to the east D.two zones to the west
Dacron sails，when not in use，may be damaged if（）.A.left...
单项选择题Dacron sails，when not in use，may be damaged if（）.
A.left in the sunlight B.stowed wet C.washed with soap D.folded frequently
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
