单项选择题
A.low B.high C.warm front D.cold front
In many areas atoll clouds (clouds of vertical developm...
单项选择题In many areas atoll clouds (clouds of vertical development) are produced over small islands. These are the result of（）.
A.rising air currents produced by the warm islands B.warm air from the sea rising over higher land areas C.cool land air mixing with warm sea air D.descending air over the islands
In a microbarograph，the pen should be checked and the i...
单项选择题In a microbarograph，the pen should be checked and the ink well filled（）.
A.each time the chart is changed B.once per month C.once per week D.daily
If an observer in the Northern Hemisphere faces the sur...
单项选择题If an observer in the Northern Hemisphere faces the surface wind，the center of low pressure is to his（）.
A.left，slightly behind him B.right，slightly behind him C.left，slightly in front of him D.right，slightly in front of him
