认为怎样的英文短语

I think I could, if I only knew how to begin.

要是我知道怎么开始的话，我想我可以。

I don't think there's a specific rule about how to beat stress.

我认为关于如何战胜压力，没有具体规则。

I think it's really interesting to see how the mind can contain so much.

我想，能看到大脑能容纳这么多东西真是件有趣的事情。