There is almost no chance that Sandra dropped the milk. It is highly unlikely that Winona is a mouse. It is highly unlikely that Brian is a frog. It is impossible that if 'Sandra dropped the milk and Brian is a frog' then Bernhard is green. We believe that if either 'Sandra dropped the milk' or 'Winona is a mouse' but not both then Julius is yellow. It is probably the case that if 'Winona is a mouse and Brian is a frog' then John got the milk.
It is likely that 'Brian is a frog' or 'Julius is yellow' or both.
It is improbable that 'Brian is a frog' or 'Julius is yellow' or both.
It is likely that 'Brian is a frog' or 'Julius is yellow' 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
  0.02::factA.
  0.05::factB.
  0.05::factC.
  %hop1
  0.0::factX:-and(factA,factC).
  0.75::factY:-xor(factA,factB).
  0.7::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Brian is a frog' or 'Julius is yellow' or both.