风势渐弱。

The wind is falling.

风势缓和了。

The wind is moderating.

火借风势，越烧越旺。

Fanned by the wind, the fire burned more and more furiously.

那沉重的大雨点借着风势，竟如拧在一起的一条条钢鞭，从天空甩下来抽打每一扇脆弱的窗户，好像要把它们撕裂了一般。

With the force of wind, the lines of raindrops whipped each fragile window pane from the sky like steel scourges trying to tear them into pieces.