It is probable that Mary left the milk. Chances are slight that Lily is gray. There is a better than even chance that Julius is white. It is probable that if Mary left the milk, or Julius is white, then Brian is a lion. There is little chance that if Lily is gray, and Mary left the milk, then Greg is a swan. It is highly unlikely that if Mary left the milk, or Lily is gray, then Gertrude is a mouse.
It is improbable that either Lily is gray, or Mary left the milk.
It is probably the case that either Lily is gray, or Mary left the milk.
It is improbable that either Lily is gray, or Mary left the milk.
Either Lily is gray, or Mary left the milk.