帮我看一下这几道被动语态与主动语态互换的题

题目

帮我看一下这几道被动语态与主动语态互换的题
What was found by them?
She cannot compose such fine music.
He hasn't received the letter.
最好能再翻译一下。

答案

What did they find?他们找到了什么?
Such fine music cannot be composed by her.
这么美妙的音乐不可能被她谱写出来
The letter hasn't been received by him.
那封信还没有被他收到.