单项选择题
A.it is above 70°F B.the ground over which it moves is cooler than the air C.it originated in a high pressure area D.it originated in a low pressure area
A.steady rainfall B.hail storms C.thunderstorms D.tornadoes or waterspouts
A.drops,and the temperature drops B.drops,and the temperature rises C.rises,and the temperature drops D.rises,and the temperature rises