There is a better than even chance that Sandra left the milk. It is unlikely that Greg is green. It is impossible that John moved to the garden. It is almost certain that if 'John moved to the garden and Sandra left the milk' then Bernhard is gray. There is little chance that if 'Greg is green and Sandra left the milk' then Lily is a swan. It is unlikely that if either 'Sandra left the milk' or 'Greg is green' but not both then Julius is a lion.
It is improbable that either 'Greg is green' or 'Sandra left the milk' but not both.
There is a better than even chance that either 'Greg is green' or 'Sandra left the milk' but not both.
It is improbable that either 'Greg is green' or 'Sandra left the milk' 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
  0.6::factA.
  0.2::factB.
  0.0::factC.
  %hop1
  0.95::factX:-and(factC,factA).
  0.1::factY:-and(factB,factA).
  0.2::factZ:-xor(factA,factB).

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

  query(conclusion).
  
Either 'Greg is green' or 'Sandra left the milk' but not both.