There is almost no chance that Greg is yellow. It is probably not the case that Mary went to the kitchen. It is improbable that Lily is a lion. We believe that if 'Mary went to the kitchen' or 'Greg is yellow' or both then Sandra left the football. There is little chance that if 'Lily is a lion' or 'Greg is yellow' or both then Brian is green. There is almost no chance that if 'Mary went to the kitchen' or 'Greg is yellow' or both then John dropped the apple.
Chances are about even that 'Brian is green' or 'John dropped the apple' or both.
There is almost no chance that 'Brian is green' or 'John dropped the apple' or both.
Chances are about even that 'Brian is green' or 'John dropped the apple' or 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
  0.02::factA.
  0.25::factB.
  0.1::factC.
  %hop1
  0.75::factX:-or(factB,factA).
  0.1::factY:-or(factC,factA).
  0.02::factZ:-or(factB,factA).

  %hop2
  conclusion:-or(factY,factZ).

  query(conclusion).
  
'Brian is green' or 'John dropped the apple' or both.