It is impossible that John discarded the apple. We believe that Greg is white. It is likely that Julius is a frog. It is improbable that if either John discarded the apple, or Julius is a frog, then Sandra left the football. There is little chance that if either John discarded the apple, or Julius is a frog, then Mary went to the office. There is almost no chance that if Julius is a frog, or John discarded the apple, then Bernhard is a swan.
It is highly unlikely that sandra left the football, or John discarded the apple.
It is highly unlikely that sandra left the football, or John discarded the apple.
Chances are about even that sandra left the football, or John discarded the apple.
Sandra left the football, or John discarded the apple.