YOU SAID:
You've done this, haven't you
INTO JAPANESE
あなたはこれをやったことがありますか？
BACK INTO ENGLISH
Have you done this?
INTO JAPANESE
なんでこんな事したの?
BACK INTO ENGLISH
Why have you done this?
INTO JAPANESE
なんでこんな事したの?
BACK INTO ENGLISH
Why have you done this?
That didn't even make that much sense in English.
