It is impossible that Daniel dropped the milk. It is unlikely that Brian is a frog. We doubt that Jeff put down the apple.
It is probable that either Jeff put down the apple, or Brian is a frog.
It is probably not the case that either Jeff put down the apple, or Brian is a frog.
It is probable that either Jeff put down the apple, or Brian is a frog.
Either Jeff put down the apple, or Brian is a frog.