YOU SAID:

I can’t remember how it happened, or why it did

INTO JAPANESE

それがどのように起こったのか、なぜ起こったのかは思い出せない

BACK INTO ENGLISH

I can't remember how it happened or why it happened.

INTO JAPANESE

それがどのように起こったのか、なぜ起こったのか思い出せません。

BACK INTO ENGLISH

I can't remember how it happened or why it happened.