after和behind的用法区别

例句：

I am a seeker after truth.

我是一名真理的追求者。

After the revolution, anarchy ruled.

革命以后，无政府主义大行其道。

She died shortly after giving birth.

她生下孩子后不久便死了。

What's the idea behind this?

这背后的意图是什么？

The sun went behind a cloud.

太阳躲在了一朵云的'后面。

He crouched behind a low hedgerow.

他蹲在一排低矮的灌木篱后面。