单项选择题 （）forms over land，most frequently during autumn and winter over low-lying land，especially if it is damp and marshy and in valleys on quiet nights with clear skies.

单项选择题 （） blow more or less constantly（except when monsoons prevail）throughout all seasons at a mean speed of around 14 knots and are generally strongest in the late winter.

单项选择题 （）are experienced in temperate latitudes during warn summer weather but rarely exceed Force 3 and may extend 10 to 15 miles on either side of the coastline.