单项选择题
A.cold front has passed
B.low pressure center is approaching
C.stationary front exists
D.high pressure center has passed
单项选择题 In the Northern Hemisphere，what type of cloud formations would you expect to see to the west of an approaching tropical wave?（）.
单项选择题 In the Northern Hemisphere，the largest waves or swells created by a typhoon or hurricane will be located（）.
单项选择题 In the Northern Hemisphere，gusty winds shifting clockwise，a rapid drop in temperature，thunderstorms or rain squalls in summer (frequent rain/snow squalls in winter) then a rise in pressure followed by clearing skies，indicate the passage of a(n)（） .