It is impossible that Brian is a swan. It is likely that Julius is gray. It is likely that Lily is a lion. It is almost certain that if either 'Julius is gray' or 'Brian is a swan' but not both then Greg is yellow. It is certain that if 'Lily is a lion' or 'Brian is a swan' or both then John got the apple. Chances are about even that if either 'Julius is gray' or 'Lily is a lion' but not both then Mary dropped the milk.
It is impossible that 'Mary dropped the milk and Brian is a swan'.
It is impossible that 'Mary dropped the milk and Brian is a swan'.
Chances are about even that 'Mary dropped the milk and Brian 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
  0.0::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.95::factX:-xor(factB,factA).
  1.0::factY:-or(factC,factA).
  0.5::factZ:-xor(factB,factC).

  %hop2
  conclusion:-and(factZ,factA).

  query(conclusion).
  
'Mary dropped the milk and Brian is a swan'.