YOU SAID:

I saw him dancing there By the record machine I knew he must have Been about seventeen The beat was going strong Playing my favorite song

INTO JAPANESE

私は彼がそこに踊っているのを見ました。

BACK INTO ENGLISH

I saw him dancing there.

INTO JAPANESE

私は彼がそこで踊っているのを見た。

BACK INTO ENGLISH

I saw him dancing there.