墙上一棵草，风吹两边倒。

A tuft of grass atop the wall sways right and left in the wind.

只要能更好为他们的目的服务，他们甚至可以象墙头草一样在冲突的双方两边倒。

They would even play both sides of the conflict against each other if doing so would serve to further their own goals.