It seems you've burned yourself out.
Pardon. I'm afraid I didn't quite catch you.
You look tired. You must have overworked yourself.
Yes, a little bit. I've been hitting the books all these days.
Why have you been studying so hard?
I need to review my English.
So that's what keeps you so busy recently!
Yes, I've been tied up with my studies. Now, what worries me a lot is my English.
But why? Your English is very good.
Thank you. You are very kind.
No, I'm telling the truth. As an American, I understand you quite well.
It's very kind of you to say so.