题目内容：

the room has been cleaned by tom 对tom提问
____ ____the room____ cleaned ____

优质解答

一看就知道是中国人出的题.Who/whom,has,been,by

追问：

怎么感觉有点不对呢

追答：

是正确的，一般是: By whom has the room been cleaned. 但是空有限制。