It is unlikely that Lily is a swan. It is unlikely that Mary went to the kitchen. There is almost no chance that Sumit is thirsty. We believe that if 'Mary went to the kitchen and Lily is a swan' then Julius is white. We believe that if 'Sumit is thirsty' or 'Mary went to the kitchen' or both then Greg is a rhino. We doubt that if 'Sumit is thirsty' or 'Mary went to the kitchen' or both then Brian is white.
It is highly likely that either 'Sumit is thirsty' or 'Lily is a swan' but not both.
We doubt that either 'Sumit is thirsty' or 'Lily is a swan' but not both.
It is highly likely that either 'Sumit is thirsty' 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
  0.2::factA.
  0.2::factB.
  0.02::factC.
  %hop1
  0.75::factX:-and(factB,factA).
  0.75::factY:-or(factC,factB).
  0.2::factZ:-or(factC,factB).

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

  query(conclusion).
  
Either 'Sumit is thirsty' or 'Lily is a swan' but not both.