YOU SAID:

'Cause what you don't understand is

INTO JAPANESE

原因は理解していないもの

BACK INTO ENGLISH

Do not understand what is the cause

INTO JAPANESE

何が原因かわからない

BACK INTO ENGLISH

Do not know what causes it?

INTO JAPANESE

何が原因かわからないですか。

BACK INTO ENGLISH

Do not know what causes it.

INTO JAPANESE

何が原因か分からない。

BACK INTO ENGLISH

Do not know what causes it.