YOU SAID:
I am very very happy! I am not sure why
INTO JAPANESE
とても嬉しいです!理由はわかりません
BACK INTO ENGLISH
I am very happy! I don't know why.
INTO JAPANESE
とても嬉しいです!どうしてか知りません。
BACK INTO ENGLISH
I am very happy! I don't know why.
You've done this before, haven't you.