YOU SAID:
I rode my horse on Friday to school but then he threw me off and I broke my leg.
INTO JAPANESE
私は金曜日に馬に乗って学校に行きましたが、彼は私を投げ捨て、私は足を骨折しました。
BACK INTO ENGLISH
I went to school on a horse on Friday, but he threw me away and I broke my leg.
INTO JAPANESE
私は金曜日に馬で学校に行きましたが、彼は私を捨て、私は私の足を折りました。
BACK INTO ENGLISH
I went to school on a horse on Friday, but he abandoned me and I broke my leg.
INTO JAPANESE
私は金曜日に馬に乗って学校に行きましたが、彼は私を捨てて、私は足を骨折しました。
BACK INTO ENGLISH
I went to school on a horse on Friday, but he abandoned me and I broke my leg.
That didn't even make that much sense in English.