他表现得好像以前从未见过我一样。

He ___acted as if he'd never met me before.

别这么傻——你表现得像个孩子！

Don't be so silly - you're ___acting like a child!

我总是关心我有多少钱，而且我总是表现得很理智。

I always care about how much money I have and I always ___act sensibly.