YOU SAID:

Once i was sitting in a chair, suddenly my chair broke. Now i,m very sad.

INTO JAPANESE

椅子に座っていると、突然椅子が壊れました。今、私はとても悲しいです。

BACK INTO ENGLISH

When I was sitting in a chair, the chair suddenly broke. I'm very sad now.

INTO JAPANESE

私が椅子に座っていたとき、椅子が突然壊れました。今はとても悲しいです。

BACK INTO ENGLISH

When I was sitting in a chair, the chair suddenly broke. I'm very sad now.