YOU SAID:
I need to do grocery shopping.
INTO JAPANESE
食料品買い物をする必要があります。
BACK INTO ENGLISH
We need to shop for groceries.
INTO JAPANESE
私たちは食料品を買う必要があります。
BACK INTO ENGLISH
We need to buy groceries.
INTO JAPANESE
私たちは食料品を購入する必要があります。
BACK INTO ENGLISH
We need to buy groceries.
That didn't even make that much sense in English.