YOU SAID:

I don't understand what he's trying to ask.

INTO JAPANESE

私は彼が何をしようとしているのお願いを理解しません。

BACK INTO ENGLISH

I try what he was doing you do not understand.

INTO JAPANESE

私は彼が何をやっていたしようと理解していません。

BACK INTO ENGLISH

I was doing what he was understood.

INTO JAPANESE

彼が何をやっていた理解します。

BACK INTO ENGLISH

He was doing what you understand.

INTO JAPANESE

彼を理解していた。

BACK INTO ENGLISH

He was understanding.

INTO JAPANESE

彼は理解しました。

BACK INTO ENGLISH

He was understanding.