It is highly likely that Sandra is in the kitchen. It is probably the case that Winona is a wolf. It is improbable that Greg is white. It is highly likely that if 'Sandra is in the kitchen' or 'Winona is a wolf' or both then Bill moved to the office. We believe that if 'Greg is white and Sandra is in the kitchen' then Fred left the football. It is highly unlikely that if 'Sandra is in the kitchen' or 'Greg is white' or both then Bernhard is a rhino.
It is probably the case that 'Fred left the football' or 'Winona is a wolf' or both.
It is probably the case that 'Fred left the football' or 'Winona is a wolf' or both.
We doubt that 'Fred left the football' or 'Winona is a wolf' 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
  0.9::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.9::factX:-or(factA,factB).
  0.75::factY:-and(factC,factA).
  0.05::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Fred left the football' or 'Winona is a wolf' or both.