YOU SAID:
Fill up my car while you're at it.
INTO JAPANESE
あなたがそれにいる間に私の車をいっぱいにしてください。
BACK INTO ENGLISH
Fill my car while you are in it.
INTO JAPANESE
あなたがそれにいる間に私の車を埋めてください。
BACK INTO ENGLISH
Fill my car while you are in it.
You should move to Japan!