There is almost no chance that Gertrude is a cat. It is probably not the case that Brian is a rhino. It is probably the case that Sandra took the milk. It is impossible that if either 'Sandra took the milk' or 'Brian is a rhino' but not both then Lily is a lion. It is probable that if either 'Sandra took the milk' or 'Gertrude is a cat' but not both then John went to the bedroom. We doubt that if 'Sandra took the milk and Brian is a rhino' then Julius is a frog.
It is impossible that 'Gertrude is a cat and John went to the bedroom'.
It is impossible that 'Gertrude is a cat and John went to the bedroom'.
There is a better than even chance that 'Gertrude is a cat and John went to the bedroom'.

  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
  0.02::factA.
  0.25::factB.
  0.7::factC.
  %hop1
  0.0::factX:-xor(factC,factB).
  0.7::factY:-xor(factC,factA).
  0.2::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Gertrude is a cat and John went to the bedroom'.