It is certain that Greg is a swan. It is probably not the case that John picked up the milk. It is impossible that Julius is gray. It is probable that if Greg is a swan, or John picked up the milk, then Sandra got the apple. We doubt that if Greg is a swan, and John picked up the milk, then Brian is a frog. It is almost certain that if Greg is a swan, and Julius is gray, then Lily is yellow.
It is certain that either Julius is gray, or Greg is a swan.
It is certain that either Julius is gray, or Greg is a swan.
We doubt that either Julius is gray, or Greg is a swan.
Either Julius is gray, or Greg is a swan.