drain diffusion

例句：

1. 1. The water in the soil is being drained by the underground river.
   地下河流正在将土壤中的水分排干。
2. 2. The process of diffusion is a natural way for gases to move through a liquid or solid.
   扩散过程是气体通过液体或固体的自然方式。
3. 3. The oil was spread out over the surface of the water, causing it to drain away quickly.
   油被撒在水面上，导致它迅速流失。