YOU SAID:
I was at the store with my mother last week
INTO JAPANESE
私は先週母と一緒に店にいました
BACK INTO ENGLISH
I was at the store with my mother last week.
INTO JAPANESE
私は先週母と一緒に店にいました。
BACK INTO ENGLISH
I was at the store with my mother last week.
That didn't even make that much sense in English.