YOU SAID:

You have no idea how much you've forgotten.

INTO JAPANESE

どれだけ忘れているのかわかりません。

BACK INTO ENGLISH

I don't know how much I have forgotten.

INTO JAPANESE

どれだけ忘れたかわかりません。

BACK INTO ENGLISH

I don't know how much I forgot.

INTO JAPANESE

どれだけ忘れたかわかりません。

BACK INTO ENGLISH

I don't know how much I forgot.