It is highly unlikely that Bill left the milk. There is little chance that Mary went to the office. It is impossible that Bernhard is a frog.
It is highly unlikely that either Bernhard is a frog, or Bill left the milk.
It is highly unlikely that either Bernhard is a frog, or Bill left the milk.
It is probably the case that either Bernhard is a frog, or Bill left the milk.
Either Bernhard is a frog, or Bill left the milk.