There is little chance that Sandra took the football. It is improbable that John got the apple. Chances are about even that Julius is yellow. Chances are slight that if 'Julius is yellow and Sandra took the football' then Jessica is a cat. It is unlikely that if 'Julius is yellow' or 'John got the apple' or both then Bernhard is gray. There is a better than even chance that if 'Sandra took the football' or 'Julius is yellow' or both then Brian is a frog.
There is almost no chance that 'Julius is yellow' or 'John got the apple' or both.
There is a better than even chance that 'Julius is yellow' or 'John got the apple' or both.
There is almost no chance that 'Julius is yellow' or 'John got 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
  0.1::factA.
  0.1::factB.
  0.5::factC.
  %hop1
  0.1::factX:-and(factC,factA).
  0.2::factY:-or(factC,factB).
  0.6::factZ:-or(factA,factC).

  %hop2
  conclusion:-or(factC,factB).

  query(conclusion).
  
'Julius is yellow' or 'John got the apple' or both.