The prevailing wind is the wind direction most often observed during a given time period. Wind speed is the rate at which the air moves past a stationary object.

单项选择题Education in Russia and the other new countries faces especially daunting obstacles because the struggling economies of these nations often provide insufficient funds for education.

单项选择题Australia began to assume its modern configuration by the Eocene Epoch, some 50 million years ago, when Antarctica broke away and drifted southward.