YOU SAID:
the horse runs for miles and miles
INTO JAPANESE
馬は何マイルも走ります
BACK INTO ENGLISH
horses run for miles
INTO JAPANESE
馬は何マイルも走る
BACK INTO ENGLISH
horses run many miles
INTO JAPANESE
馬は何マイルも走ります
BACK INTO ENGLISH
horses run for miles
INTO JAPANESE
馬は何マイルも走る
BACK INTO ENGLISH
horses run many miles
it is unlikely that this phrase will ever reach equilibrium