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。