YOU SAID:
Ive been in the hills
INTO JAPANESE
丘に行ったことがある
BACK INTO ENGLISH
I've been to the hills.
INTO JAPANESE
私は丘に行ったことがある。
BACK INTO ENGLISH
I have been to the hills.
INTO JAPANESE
私は丘に行ったことがある。
BACK INTO ENGLISH
I have been to the hills.
That didn't even make that much sense in English.