单项选择题 In Beaufort Scale，the wind force 7 with speed of 28-33 knots is defined as（）.

单项选择题 If your weather bulletin shows the center of a low pressure area to be 100 miles due east of your position，what winds can you expect in the Northern Hemisphere?（）.

单项选择题 If the sky was clear，with the exception of a few cumulus clouds，it would indicate（）.