Anticyclones are usually characterized by（）.

单项选择题An occluded front on a weather map is colored（）.

A.blue line
B.purple line
C.dashed blue line
D.alternate red and blue line

单项选择题An aneroid barometer is an instrument（）.

A.used to measure the speed of wind
B.in which the pressure of the air is measured
C.that tells which direction a storm is coming from
D.used to measure the height of waves

单项选择题An air mass is termed warm if（）.

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

单项选择题All of the following are associated with cumulonimbus clouds EXCEPT（）.

A.steady rainfall
B.hail storms
C.thunderstorms
D.tornadoes or waterspouts

单项选择题After a cold front passes，the barometric pressure（）.

A.drops，and the temperature drops
B.drops，and the temperature rises
C.rises，and the temperature drops
D.rises，and the temperature rises