It is improbable that Greg is gray. We believe that Bernhard is a frog. We believe that Sumit is tired. It is probably not the case that if Greg is gray, or Bernhard is a frog, then John left the football. It is probably the case that if either Sumit is tired, or Bernhard is a frog, then Bill dropped the milk. Chances are slight that if Bernhard is a frog, or Sumit is tired, then Mary took the apple.
It is probably not the case that either John left the football, or Sumit is tired.
It is probable that either John left the football, or Sumit is tired.
It is probably not the case that either John left the football, or Sumit is tired.
Either John left the football, or Sumit is tired.