It is likely that Brian is white. There is little chance that Sandra got the milk. It is probably not the case that Greg is a swan. It is certain that if 'Brian is white' or 'Sandra got the milk' or both then Julius is a frog. There is a very good chance that if 'Sandra got the milk and Brian is white' then Mary put down the apple. We doubt that if either 'Sandra got the milk' or 'Brian is white' but not both then Lily is a swan.
It is probably the case that 'Brian is white and Mary put down the apple'.
It is highly unlikely that 'Brian is white and Mary put down the apple'.
It is probably the case that 'Brian is white and Mary put down the apple'.

  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.
  0.1::factB.
  0.25::factC.
  %hop1
  1.0::factX:-or(factA,factB).
  0.8::factY:-and(factB,factA).
  0.2::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Brian is white and Mary put down the apple'.