There is almost no chance that Julius is a lion. It is probably not the case that Jeff put down the milk. There is a better than even chance that Mary left the apple. It is improbable that if either 'Jeff put down the milk' or 'Mary left the apple' but not both then Brian is gray. We doubt that if 'Julius is a lion and Mary left the apple' then Lily is a swan. There is a better than even chance that if either 'Jeff put down the milk' or 'Julius is a lion' but not both then John took the football.
It is highly likely that 'Brian is gray' or 'John took the football' or both.
We doubt that 'Brian is gray' or 'John took the football' or both.
It is highly likely that 'Brian is gray' or 'John took the football' 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.
  0.6::factC.
  %hop1
  0.1::factX:-xor(factB,factC).
  0.2::factY:-and(factA,factC).
  0.6::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Brian is gray' or 'John took the football' or both.