We didn't like each other at first. [=when we met]起初我们并不喜欢彼此。

At first I thought she was crying, but then I realized she was actually laughing.一开始，我以为她在哭，但后来发现她其实是在笑。

The book bored me at first. [=initially]这本书我刚开始读的时候觉得没意思。