Chances are about even that Bernhard is green. There is little chance that Sandra left the football. It is probably the case that Julius is a lion. There is little chance that if 'Julius is a lion and Sandra left the football' then John moved to the office. It is unlikely that if either 'Sandra left the football' or 'Julius is a lion' but not both then Jeff dropped the apple. It is certain that if 'Julius is a lion' or 'Sandra left the football' or both then Brian is a rhino.
Chances are slight that 'Jeff dropped the apple' or 'Brian is a rhino' or both.
We believe that 'Jeff dropped the apple' or 'Brian is a rhino' or both.
Chances are slight that 'Jeff dropped the apple' or 'Brian is a rhino' 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
  0.5::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.1::factX:-and(factC,factB).
  0.2::factY:-xor(factB,factC).
  1.0::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Jeff dropped the apple' or 'Brian is a rhino' or both.