It is probable that Bernhard is gray. We doubt that Mary moved to the garden. It is almost certain that Julius is a swan. It is impossible that if 'Julius is a swan' or 'Mary moved to the garden' or both then Jason is tired. There is little chance that if 'Julius is a swan' or 'Mary moved to the garden' or both then Winona is a cat. It is highly likely that if either 'Julius is a swan' or 'Mary moved to the garden' but not both then Lily is a frog.
It is probable that either 'Bernhard is gray' or 'Winona is a cat' but not both.
It is probable that either 'Bernhard is gray' or 'Winona is a cat' but not both.
There is almost no chance that either 'Bernhard is gray' or 'Winona is a cat' 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
  0.7::factA.
  0.2::factB.
  0.95::factC.
  %hop1
  0.0::factX:-or(factC,factB).
  0.1::factY:-or(factC,factB).
  0.9::factZ:-xor(factC,factB).

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

  query(conclusion).
  
Either 'Bernhard is gray' or 'Winona is a cat' but not both.