YOU SAID:
Billy went to the store with his parents
INTO JAPANESE
ビリーは両親と一緒に店に行った
BACK INTO ENGLISH
Billy went to the store with his parents.
INTO JAPANESE
ビリーは両親と一緒に店に行きました。
BACK INTO ENGLISH
Billy went to the store with his parents.
That didn't even make that much sense in English.