Nanyue is a small town, we can see many tourists who come from different parts of the world there.

A. Because                 B. Unless                  C. Although

在重力除油罐中重力除油的两个过程是（）。

A.上流速度推动浮升的过程和对流碰撞聚结过程

B.上升过程和下降过程

C.下降过程和对流碰撞过程

D.浮升过程和对流碰撞过程