YOU SAID:

I walk to the shop and bought some green bananas.

INTO JAPANESE

私は店に歩いて緑のバナナを買った。

BACK INTO ENGLISH

I walked to the store and bought a green banana.

INTO JAPANESE

私はその店に歩いて行き、緑色のバナナを買いました。

BACK INTO ENGLISH

I walked to the store and bought a green banana.