YOU SAID:

the river ran as i run rivals

INTO JAPANESE

川は私がライバルを走らせるように走った

BACK INTO ENGLISH

The river ran like I ran a rival

INTO JAPANESE

ライバルを走らせたように川が流れた

BACK INTO ENGLISH

The river flowed like a rival

INTO JAPANESE

川はライバルのように流れた

BACK INTO ENGLISH

The river flowed like a rival