It is impossible that Brian is yellow. We believe that Julius is a frog. It is highly likely that Mary got the apple. There is almost no chance that if 'Brian is yellow and Julius is a frog' then Lily is green. It is likely that if 'Brian is yellow and Mary got the apple' then Daniel took the football. It is unlikely that if 'Julius is a frog and Brian is yellow' then Bernhard is a swan.
It is highly unlikely that either 'Julius is a frog' or 'Lily is green' but not both.
We believe that either 'Julius is a frog' or 'Lily is green' but not both.
It is highly unlikely that either 'Julius is a frog' or 'Lily is green' 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
  0.02::factX:-and(factA,factB).
  0.7::factY:-and(factA,factC).
  0.2::factZ:-and(factB,factA).

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

  query(conclusion).
  
Either 'Julius is a frog' or 'Lily is green' but not both.