YOU SAID:

I threw a rock at the river, causing it to skip.

INTO JAPANESE

私は川に石を投げ、それをスキップさせました。

BACK INTO ENGLISH

I threw a stone into the river and let it skip.

INTO JAPANESE

私は石を川に投げ込み、それをスキップさせました。

BACK INTO ENGLISH

I threw a stone into the river and let it skip.