It is improbable that Jeff went to the bedroom. There is little chance that Greg is white. We believe that Fred dropped the apple. It is probably the case that if 'Fred dropped the apple' or 'Greg is white' or both then Julius is green. It is unlikely that if 'Jeff went to the bedroom' or 'Greg is white' or both then John moved to the garden. It is probable that if either 'Fred dropped the apple' or 'Greg is white' but not both then Bernhard is a lion.
We believe that 'Fred dropped the apple' or 'John moved to the garden' or both.
We believe that 'Fred dropped the apple' or 'John moved to the garden' or both.
We doubt that 'Fred dropped the apple' or 'John moved to the garden' 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.
  0.75::factC.
  %hop1
  0.7::factX:-or(factC,factB).
  0.2::factY:-or(factA,factB).
  0.7::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Fred dropped the apple' or 'John moved to the garden' or both.