It is impossible that Lily is white. It is highly likely that Julius is a rhino. It is probably not the case that John picked up the apple. There is almost no chance that if either 'John picked up the apple' or 'Julius is a rhino' but not both then Fred left the football. It is unlikely that if either 'Julius is a rhino' or 'John picked up the apple' but not both then Gertrude is a sheep. It is probably not the case that if 'Julius is a rhino and John picked up the apple' then Mary went to the bedroom.
It is almost certain that either 'John picked up the apple' or 'Gertrude is a sheep' but not both.
Chances are about even that either 'John picked up the apple' or 'Gertrude is a sheep' but not both.
It is almost certain that either 'John picked up the apple' or 'Gertrude is a sheep' 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.
  0.9::factB.
  0.25::factC.
  %hop1
  0.02::factX:-xor(factC,factB).
  0.2::factY:-xor(factB,factC).
  0.25::factZ:-and(factB,factC).

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

  query(conclusion).
  
Either 'John picked up the apple' or 'Gertrude is a sheep' but not both.