下列词语中加线的字，每对读音都不相同的一组是(　　)

It was _______ she was injured in the accident _______ she didn’t come to the party yesterday.

We should start to do our homework right now. We must not _______ until tomorrow what we can do today.

My bedroom looks a little smaller， but__________.

It ___________ that he has been ill for a long time.