It is unlikely that Greg is a swan. There is almost no chance that Daniel dropped the milk. We believe that Brian is yellow. Chances are slight that if either 'Daniel dropped the milk' or 'Greg is a swan' but not both then Julius is gray. Chances are slight that if 'Greg is a swan' or 'Brian is yellow' or both then Lily is a frog. It is probably the case that if 'Greg is a swan and Daniel dropped the milk' then Mary went to the office.
It is probably the case that 'Lily is a frog' or 'Greg is a swan' or both.
It is probably not the case that 'Lily is a frog' or 'Greg is a swan' or both.
It is probably the case that 'Lily is a frog' or 'Greg is a swan' 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
  0.2::factA.
  0.02::factB.
  0.75::factC.
  %hop1
  0.1::factX:-xor(factB,factA).
  0.1::factY:-or(factA,factC).
  0.7::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Lily is a frog' or 'Greg is a swan' or both.