It is probably the case that Lily is yellow. It is highly likely that Julius is white. We doubt that John discarded the apple. We believe that if 'John discarded the apple and Lily is yellow' then Bernhard is yellow. It is almost certain that if 'Lily is yellow and John discarded the apple' then Greg is a frog. It is unlikely that if 'John discarded the apple' or 'Lily is yellow' or both then Mary left the milk.
Chances are slight that 'Greg is a frog and John discarded the apple'.
Chances are slight that 'Greg is a frog and John discarded the apple'.
It is likely that 'Greg is a frog and John discarded the apple'.

  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.
  0.9::factB.
  0.2::factC.
  %hop1
  0.75::factX:-and(factC,factA).
  0.95::factY:-and(factA,factC).
  0.2::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Greg is a frog and John discarded the apple'.