There is a very good chance that Mary left the football. It is probable that Sumit is bored. It is almost certain that Julius is gray. There is little chance that if either 'Mary left the football' or 'Julius is gray' but not both then Winona is a wolf. We believe that if 'Julius is gray and Sumit is bored' then John got the milk. Chances are about even that if 'Julius is gray and Mary left the football' then Bernhard is a lion.
It is probably the case that either 'Julius is gray' or 'Sumit is bored' but not both.
It is probably not the case that either 'Julius is gray' or 'Sumit is bored' but not both.
It is probably the case that either 'Julius is gray' or 'Sumit is bored' 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
  0.8::factA.
  0.7::factB.
  0.95::factC.
  %hop1
  0.1::factX:-xor(factA,factC).
  0.75::factY:-and(factC,factB).
  0.5::factZ:-and(factC,factA).

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

  query(conclusion).
  
Either 'Julius is gray' or 'Sumit is bored' but not both.