YOU SAID:
Who could have done this?
INTO JAPANESE
人はこれを行っている可能性が?
BACK INTO ENGLISH
Could people have done this?
INTO JAPANESE
人これを行っているか。
BACK INTO ENGLISH
Who would have done this.
INTO JAPANESE
人はこれをやっているでしょう。
BACK INTO ENGLISH
People who are doing this.
INTO JAPANESE
これをやっている人。
BACK INTO ENGLISH
People who are doing this.
You've done this before, haven't you.