单项选择题
In reading a weather map，closely spaced pressure gradient lines would indicate（）.
A.high winds B.high overcast clouds C.calm or light winds D.fog or steady rain
单项选择题 In North America the majority of the weather systems move from（）.
单项选择题 In bad weather，what length of chain should be used with a single anchor? （）
单项选择题 In a storm，the leeward lines of a ship’s mooring system will（）.
