YOU SAID:

i went to the car and forgot my keys

INTO JAPANESE

私は車に行って、私の鍵を忘れた

BACK INTO ENGLISH

I went to the car and forgot my key.

INTO JAPANESE

私は車に行き、鍵を忘れた。

BACK INTO ENGLISH

I went to the car and forgot the key.

INTO JAPANESE

車に行って鍵を忘れてしまいました。

BACK INTO ENGLISH

I went to the car and forgot my key.

INTO JAPANESE

私は車に行き、鍵を忘れた。

BACK INTO ENGLISH

I went to the car and forgot the key.

INTO JAPANESE

車に行って鍵を忘れてしまいました。