after和behind的用法區別

例句：

I am a seeker after truth.

我是一名真理的追求者。

After the revolution, anarchy ruled.

革命以後，無政府主義大行其道。

She died shortly after giving birth.

她生下孩子後不久便死了。

What's the idea behind this?

這背後的意圖是什麼？

The sun went behind a cloud.

太陽躲在了一朵雲的'後面。

He crouched behind a low hedgerow.

他蹲在一排低矮的灌木籬後面。