Sometimes I forget why I'm doing, what I'm doing.

有时候我忘了为什么我在做，我在做什么。

Have you ever done that?

你曾有过这种经历吗？

I'm not just talking about a memory problem, although that's possible too.

我并不仅仅是在谈论记忆问题，虽然那也是有可能的。

I have called someone because I want to tell them something.

我曾经打电话给某人，因为我想告诉他们什么。

And then, after just choosing the place for a while, not talking about anything particular.

然后，在选择合适的地方后，还没有谈论什么特别的东西的时候。

Well, I forget why I called that person in the first place.

哦，我忘记了自己为什么要首先给那人打电话。