It is highly likely that Lily is green. There is a better than even chance that John picked up the apple. There is little chance that Julius is gray. It is certain that if 'Julius is gray and John picked up the apple' then Brian is a lion. It is probable that if 'John picked up the apple and Lily is green' then Greg is a frog. It is probably not the case that if 'Julius is gray' or 'John picked up the apple' or both then Mary is in the bathroom.
There is a very good chance that either 'Lily is green' or 'Julius is gray' but not both.
There is a very good chance that either 'Lily is green' or 'Julius is gray' but not both.
We doubt that either 'Lily is green' or 'Julius is gray' 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
  0.9::factA.
  0.6::factB.
  0.1::factC.
  %hop1
  1.0::factX:-and(factC,factB).
  0.7::factY:-and(factB,factA).
  0.25::factZ:-or(factC,factB).

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

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