It is highly likely that Julius is a lion. We believe that Greg is a frog. Chances are slight that John moved to the office. There is almost no chance that if 'Greg is a frog' or 'Julius is a lion' or both then Lily is a rhino. There is a better than even chance that if 'Greg is a frog' or 'Julius is a lion' or both then Mary put down the milk. It is impossible that if either 'John moved to the office' or 'Julius is a lion' but not both then Brian is yellow.
There is almost no chance that either 'Mary put down the milk' or 'Julius is a lion' but not both.
Chances are about even that either 'Mary put down the milk' or 'Julius is a lion' but not both.
There is almost no chance that either 'Mary put down the milk' or 'Julius is a lion' 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
  0.9::factA.
  0.75::factB.
  0.1::factC.
  %hop1
  0.02::factX:-or(factB,factA).
  0.6::factY:-or(factB,factA).
  0.0::factZ:-xor(factC,factA).

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

  query(conclusion).
  
Either 'Mary put down the milk' or 'Julius is a lion' but not both.