YOU SAID:

I eat a cookie with chocolate while writing with pen

INTO JAPANESE

ペンで書いている間、チョコレートと一緒にクッキーを食べます

BACK INTO ENGLISH

Eat cookies with chocolate while writing with a pen

INTO JAPANESE

ペンで書きながらチョコレートでクッキーを食べる

BACK INTO ENGLISH

Eat cookies with chocolate while writing with a pen