There is little chance that Lily is a frog. It is almost certain that Sandra left the milk. It is almost certain that Bernhard is yellow. It is improbable that if 'Sandra left the milk' or 'Lily is a frog' or both then Jeff moved to the garden. It is probable that if 'Lily is a frog' or 'Bernhard is yellow' or both then John put down the milk. There is almost no chance that if 'Sandra left the milk' or 'Lily is a frog' or both then Gertrude is a mouse.
It is highly likely that either 'Lily is a frog' or 'Bernhard is yellow' but not both.
It is highly likely that either 'Lily is a frog' or 'Bernhard is yellow' but not both.
Chances are slight that either 'Lily is a frog' or 'Bernhard is yellow' 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.
  0.95::factC.
  %hop1
  0.1::factX:-or(factB,factA).
  0.7::factY:-or(factA,factC).
  0.02::factZ:-or(factB,factA).

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

  query(conclusion).
  
Either 'Lily is a frog' or 'Bernhard is yellow' but not both.