It is impossible that Daniel put down the milk. We believe that John moved to the office. It is highly likely that Julius is a frog. It is unlikely that if 'Julius is a frog' or 'Daniel put down the milk' or both then Brian is a swan. It is improbable that if 'Julius is a frog and Daniel put down the milk' then Sandra took the football. It is probably not the case that if 'John moved to the office and Julius is a frog' then Emily is a sheep.
There is a very good chance that either 'Daniel put down the milk' or 'Brian is a swan' but not both.
We doubt that either 'Daniel put down the milk' or 'Brian is a swan' but not both.
There is a very good chance that either 'Daniel put down the milk' or 'Brian 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
  0.0::factA.
  0.75::factB.
  0.9::factC.
  %hop1
  0.2::factX:-or(factC,factA).
  0.1::factY:-and(factC,factA).
  0.25::factZ:-and(factB,factC).

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

  query(conclusion).
  
Either 'Daniel put down the milk' or 'Brian is a swan' but not both.