1. By then, however, in many places the grass had already taken root.
    然而到那时，很多地方的草已经生了根。

2. I stumbled over a tree root.
    树根绊了我的脚.

3. For many people, the root of their stress is anger, and the trick is to find out where the anger is coming from.
    对许多人来说，压力的根源是愤怒，而对付愤怒的诀窍是找出怒从何来。