单项选择题
A series of brief showers accompanied by strong，shifting winds may occur along or some distance ahead of a(n)（）.
A.upper front aloft B.cyclone C.occluded front D.cold front
单项选择题 A sea breeze is a wind（）.
单项选择题 A line of clouds，sharp changes in wind direction，and squalls are most frequently associated with a(n)（）.
单项选择题 A hygrometer is a device used for determining（）.
