Keep your hands off. You are mussing her hair up.

把手拿开，你把我的头发弄乱了。

I'm not crawling about in that dusty attic and mussing up my new dress.

我才不高兴在那个满是灰尘的楼上爬来爬去弄脏我的新衣服哩。

He snickered and, after mussing my hair, bounded off after the other two.

他窃笑着，弄乱了我的头发，然后紧跟着另外两人弹射出去。