It is improbable that Julius is green. There is a better than even chance that Sandra got the football. It is highly unlikely that Mary dropped the apple. There is a very good chance that if 'Mary dropped the apple and Sandra got the football' then Lily is a swan. It is improbable that if either 'Mary dropped the apple' or 'Sandra got the football' but not both then John moved to the garden. It is unlikely that if 'Sandra got the football' or 'Mary dropped the apple' or both then Greg is a rhino.
We doubt that 'Julius is green' or 'John moved to the garden' or both.
We doubt that 'Julius is green' or 'John moved to the garden' or both.
It is certain that 'Julius is green' or 'John moved to the garden' 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
  0.1::factA.
  0.6::factB.
  0.05::factC.
  %hop1
  0.8::factX:-and(factC,factB).
  0.1::factY:-xor(factC,factB).
  0.2::factZ:-or(factB,factC).

  %hop2
  conclusion:-or(factA,factY).

  query(conclusion).
  
'Julius is green' or 'John moved to the garden' or both.