We doubt that Sandra dropped the apple. We doubt that Brian is a frog. It is likely that Sumit is bored.
It is probably not the case that either Sandra dropped the apple, or Brian is a frog.
It is probably not the case that either Sandra dropped the apple, or Brian is a frog.
It is certain that either Sandra dropped the apple, or Brian is a frog.
Either Sandra dropped the apple, or Brian is a frog.