单项选择题
An occluded front is usually caused by a（）.
A.cold front becoming stationary B.warm front becoming stationary C.cold front overtaking a warm front D.warm front dissipating
单项选择题 An occluded front is caused by a(n)（）.
单项选择题 An instrument designed to maintain a continuous record of atmospheric pressure is a(n)（）.
单项选择题 An atoll cloud forming over an island due to heating of the land during the daytime would be which type? （）
