YOU SAID:

The dog sat on the bed.

INTO JAPANESE

ベッドの上に犬が座っていた。

BACK INTO ENGLISH

Dog was sitting on the bed.

INTO JAPANESE

彼女はベッドに座ってた

BACK INTO ENGLISH

She was just sitting on the bed.

INTO JAPANESE

彼女はベッドに座ってた

BACK INTO ENGLISH

She was just sitting on the bed.