It is probable that Winona is a mouse. It is probably not the case that Bernhard is green. It is likely that John discarded the apple. We doubt that if 'John discarded the apple' or 'Winona is a mouse' or both then Lily is green. It is probably the case that if 'Winona is a mouse and Bernhard is green' then Greg is gray. There is a better than even chance that if either 'Bernhard is green' or 'Winona is a mouse' but not both then Brian is yellow.
We believe that 'Greg is gray and Winona is a mouse'.
Chances are slight that 'Greg is gray and Winona is a mouse'.
We believe that 'Greg is gray and Winona is a mouse'.

  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
  0.7::factA.
  0.25::factB.
  0.7::factC.
  %hop1
  0.2::factX:-or(factC,factA).
  0.7::factY:-and(factA,factB).
  0.6::factZ:-xor(factB,factA).

  %hop2
  conclusion:-and(factY,factA).

  query(conclusion).
  
'Greg is gray and Winona is a mouse'.