YOU SAID:

I just watched a ukulele playing a skateboard while riding a human fly through space.

INTO JAPANESE

私はウクレレが空を飛んでいる間にスケートボードを見ていた。

BACK INTO ENGLISH

I was watching the skateboard while the ukulele was flying in the sky.

INTO JAPANESE

ウクレレが空を飛んでいる間、私はスケートボードを見ていた。

BACK INTO ENGLISH

While the ukulele was flying in the sky, I was watching the skateboard.

INTO JAPANESE

ウクレレが空を飛んでいる間、私はスケートボードを見ていました。

BACK INTO ENGLISH

While ukulele was flying in the sky, I was watching the skateboard.

INTO JAPANESE

ウクレレが空を飛んでいる間、私はスケートボードを見ていた。

BACK INTO ENGLISH

While the ukulele was flying in the sky, I was watching the skateboard.

INTO JAPANESE

ウクレレが空を飛んでいる間、私はスケートボードを見ていました。

BACK INTO ENGLISH

While ukulele was flying in the sky, I was watching the skateboard.