YOU SAID:

a hill mainly falls into my pocket

INTO JAPANESE

主に私のポケットに入る丘

BACK INTO ENGLISH

A hill that mainly goes into my pocket.

INTO JAPANESE

主にポケットに入る丘。

BACK INTO ENGLISH

The hills are mainly pocketed.

INTO JAPANESE

丘陵部は主に窪地となっている。

BACK INTO ENGLISH

The hills are predominantly hilly.

INTO JAPANESE

丘陵地は主に丘陵地である。

BACK INTO ENGLISH

The hills are predominantly hilly.