It is almost certain that Mary got the milk. It is highly likely that Sandra dropped the milk. It is improbable that Brian is a swan. It is impossible that if either 'Sandra dropped the milk' or 'Brian is a swan' but not both then Lily is green. There is a better than even chance that if 'Brian is a swan' or 'Sandra dropped the milk' or both then John went to the garden. It is improbable that if 'Brian is a swan and Mary got the milk' then Greg is gray.
It is almost certain that 'Brian is a swan' or 'Lily is green' or both.
There is little chance that 'Brian is a swan' or 'Lily is green' or both.
It is almost certain that 'Brian is a swan' or 'Lily is green' 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
  0.95::factA.
  0.9::factB.
  0.1::factC.
  %hop1
  0.0::factX:-xor(factB,factC).
  0.6::factY:-or(factC,factB).
  0.1::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Brian is a swan' or 'Lily is green' or both.