Chances are about even that Mary got the football. There is a very good chance that Brian is a rhino. It is improbable that Lily is a swan. It is certain that if either 'Brian is a rhino' or 'Mary got the football' but not both then John moved to the office. It is highly unlikely that if either 'Brian is a rhino' or 'Mary got the football' but not both then Emily is a wolf. It is likely that if either 'Brian is a rhino' or 'Mary got the football' but not both then Sandra left the apple.
It is almost certain that either 'Sandra left the apple' or 'Lily is a swan' but not both.
Chances are about even that either 'Sandra left the apple' or 'Lily is a swan' but not both.
It is almost certain that either 'Sandra left the apple' or 'Lily is a swan' but not 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
  0.5::factA.
  0.8::factB.
  0.1::factC.
  %hop1
  1.0::factX:-xor(factB,factA).
  0.05::factY:-xor(factB,factA).
  0.7::factZ:-xor(factB,factA).

  %hop2
  conclusion:-xor(factZ,factC).

  query(conclusion).
  
Either 'Sandra left the apple' or 'Lily is a swan' but not both.