A.clearing weather B.that a warm front has passed C.probable thunderstorm activity D.an approaching hurricane or typhoon
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
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
单项选择题Conventional anchors are least likely to hold in a bottom consisting of().
A.soft clay B.hard mud C.very soft mud D.sand
单项选择题Control of fire should be addressed().
A.immediately after restoring vital services B.immediately C.following control of flooding D.following establishment of fire boundaries
单项选择题Considering the general circulation of the atmosphere,the wind system between latitudes 30°N and 60°N is commonly called the().
A.prevailing westerlies B.horse latitudes C.trade winds D.subpolar low pressure belts