It is probable that Bernhard is gray. It is probably the case that Gertrude is a sheep. It is highly unlikely that Brian is a rhino. It is probable that if 'Brian is a rhino' or 'Gertrude is a sheep' or both then Lily is yellow. We doubt that if 'Bernhard is gray and Brian is a rhino' then Julius is a swan. We doubt that if either 'Brian is a rhino' or 'Bernhard is gray' but not both then Mary got the football.
It is almost certain that 'Lily is yellow and Julius is a swan'.
It is impossible that 'Lily is yellow and Julius is a swan'.
It is almost certain that 'Lily is yellow and Julius is a swan'.

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

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

  query(conclusion).
  
'Lily is yellow and Julius is a swan'.