It is impossible that Sandra dropped the milk. We doubt that Emily is a sheep. There is little chance that Mary went to the kitchen. We doubt that if either 'Mary went to the kitchen' or 'Sandra dropped the milk' but not both then Bernhard is white. It is unlikely that if either 'Emily is a sheep' or 'Mary went to the kitchen' but not both then Lily is green. It is likely that if 'Mary went to the kitchen and Sandra dropped the milk' then Julius is a rhino.
There is a very good chance that either 'Mary went to the kitchen' or 'Bernhard is white' but not both.
It is improbable that either 'Mary went to the kitchen' or 'Bernhard is white' but not both.
There is a very good chance that either 'Mary went to the kitchen' or 'Bernhard is white' 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
  0.0::factA.
  0.2::factB.
  0.1::factC.
  %hop1
  0.2::factX:-xor(factC,factA).
  0.2::factY:-xor(factB,factC).
  0.7::factZ:-and(factC,factA).

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

  query(conclusion).
  
Either 'Mary went to the kitchen' or 'Bernhard is white' but not both.