YOU SAID:

I need to buy ice cream at the park while eating grass

INTO JAPANESE

公園で草を食べながらアイスクリームを買わなければなりません

BACK INTO ENGLISH

I have to buy ice cream while eating grass in the park.

INTO JAPANESE

公園で草を食べながらアイスクリームを買わなければなりません。

BACK INTO ENGLISH

I have to buy ice cream while eating grass in the park.