As the warmer air rises over the cold air it also starts to cool, condensation occurs, and the cloud forming process begins, leading to rain.
随着暖空气上升到冷空气上方，它也开始冷却，出现凝结现象，云开始形成，导致降雨。
英语百科
Forming processes
Forming processes are particular manufacturing processes which make use of suitable stresses (like compression, tension, shear or combined stresses) to cause plastic deformation of the materials to produce required shapes.
During forming processes no material is removed, i.e. they are deformed and displaced.