It is certain that John discarded the apple. We doubt that Emily is a wolf. It is likely that Julius is gray. It is probable that if 'John discarded the apple' or 'Julius is gray' or both then Brian is a lion. There is a better than even chance that if 'Julius is gray' or 'John discarded the apple' or both then Bernhard is a rhino. There is a very good chance that if 'John discarded the apple' or 'Julius is gray' or both then Lily is a swan.
It is almost certain that 'Lily is a swan' or 'Julius is gray' or both.
It is almost certain that 'Lily is a swan' or 'Julius is gray' or both.
There is almost no chance that 'Lily is a swan' or 'Julius is gray' or 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
  1.0::factA.
  0.2::factB.
  0.7::factC.
  %hop1
  0.7::factX:-or(factA,factC).
  0.6::factY:-or(factC,factA).
  0.8::factZ:-or(factA,factC).

  %hop2
  conclusion:-or(factZ,factC).

  query(conclusion).
  
'Lily is a swan' or 'Julius is gray' or both.