YOU SAID:

the cat was on a party when a piano fell from the sky but he was depressed

INTO JAPANESE

ピアノが空から落ちたとき、猫はパーティーにいたが、落ち込んでいた

BACK INTO ENGLISH

The cat was at the party when the piano fell from the sky, but depressed

INTO JAPANESE

ピアノが空から落ちたとき、猫はパーティーにいたが、落ち込んだ

BACK INTO ENGLISH

The cat was at the party when the piano fell from the sky, but it was depressed

INTO JAPANESE

ピアノが空から落ちたとき、猫はパーティーにいたが、落ち込んでいた。

BACK INTO ENGLISH

When the piano fell from the sky, the cat was at the party, but depressed.

INTO JAPANESE

ピアノが空から落ちたとき、猫はパーティーにいたが落ち込んだ。

BACK INTO ENGLISH

When the piano fell from the sky, the cat was at the party, but it was depressed.

INTO JAPANESE

ピアノが空から落ちたとき、猫はパーティーにいたが、落ち込んでいた。

BACK INTO ENGLISH

When the piano fell from the sky, the cat was at the party, but depressed.

INTO JAPANESE

ピアノが空から落ちたとき、猫はパーティーにいたが落ち込んだ。

BACK INTO ENGLISH

When the piano fell from the sky, the cat was at the party, but it was depressed.