It is highly likely that Lily is green. It is certain that Brian is yellow. It is probably not the case that Emily is a sheep. We doubt that if either 'Brian is yellow' or 'Emily is a sheep' but not both then Jeff moved to the garden. We believe that if 'Emily is a sheep and Brian is yellow' then Jessica is a sheep. It is unlikely that if 'Lily is green and Brian is yellow' then Julius is a swan.
There is little chance that either 'Brian is yellow' or 'Julius is a swan' but not both.
There is a very good chance that either 'Brian is yellow' or 'Julius is a swan' but not both.
There is little chance that either 'Brian is yellow' or 'Julius 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
  0.9::factA.
  1.0::factB.
  0.25::factC.
  %hop1
  0.2::factX:-xor(factB,factC).
  0.75::factY:-and(factC,factB).
  0.2::factZ:-and(factA,factB).

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

  query(conclusion).
  
Either 'Brian is yellow' or 'Julius is a swan' but not both.