It is improbable that Winona is a mouse. It is almost certain that Mary got the football. There is little chance that Julius is a rhino. We believe that if either 'Julius is a rhino' or 'Mary got the football' but not both then John went to the hallway. It is almost certain that if 'Mary got the football and Julius is a rhino' then Gertrude is a sheep. It is probable that if 'Winona is a mouse and Julius is a rhino' then Jeff left the apple.
It is highly likely that either 'Mary got the football' or 'Gertrude is a sheep' but not both.
It is highly likely that either 'Mary got the football' or 'Gertrude is a sheep' but not both.
It is highly unlikely that either 'Mary got the football' or 'Gertrude is a sheep' but not both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.1::factA.
  0.95::factB.
  0.1::factC.
  %hop1
  0.75::factX:-xor(factC,factB).
  0.95::factY:-and(factB,factC).
  0.7::factZ:-and(factA,factC).

  %hop2
  conclusion:-xor(factB,factY).

  query(conclusion).
  
Either 'Mary got the football' or 'Gertrude is a sheep' but not both.