YOU SAID:
I think we are gonna eat potatoes.
INTO JAPANESE
ジャガイモを食べるつもりだと思います。
BACK INTO ENGLISH
I am going to eat the potatoes.
INTO JAPANESE
私はジャガイモを食べるつもりです。
BACK INTO ENGLISH
I am going to eat the potatoes.
You've done this before, haven't you.