YOU SAID:

the red fox is running in the leaves

INTO JAPANESE

キツネが葉の中を走っている

BACK INTO ENGLISH

The fox is running through the leaves

INTO JAPANESE

キツネは葉を走っています。

BACK INTO ENGLISH

The fox is running on the leaves.

INTO JAPANESE

キツネは葉の上を走っています。

BACK INTO ENGLISH

The fox runs on the leaves.

INTO JAPANESE

キツネは葉の上を走ります。

BACK INTO ENGLISH

The fox runs on the leaves.