It is certain that Lily is a rhino. There is little chance that Brian is yellow. It is almost certain that Greg is yellow. There is almost no chance that if either 'Lily is a rhino' or 'Greg is yellow' but not both then Bernhard is a swan. We doubt that if either 'Lily is a rhino' or 'Greg is yellow' but not both then Gertrude is a mouse. We doubt that if 'Greg is yellow and Brian is yellow' then Mary got the apple.
It is almost certain that 'Greg is yellow' or 'Gertrude is a mouse' or both.
It is almost certain that 'Greg is yellow' or 'Gertrude is a mouse' or both.
It is impossible that 'Greg is yellow' or 'Gertrude is a mouse' 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
  1.0::factA.
  0.1::factB.
  0.95::factC.
  %hop1
  0.02::factX:-xor(factA,factC).
  0.2::factY:-xor(factA,factC).
  0.2::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Greg is yellow' or 'Gertrude is a mouse' or both.