It is certain that Jeff dropped the apple. It is highly likely that Julius is gray. It is unlikely that Daniel left the milk. There is almost no chance that if either 'Daniel left the milk' or 'Julius is gray' but not both then Fred is in the cinema. There is almost no chance that if 'Daniel left the milk and Jeff dropped the apple' then Brian is a frog. There is almost no chance that if 'Jeff dropped the apple' or 'Julius is gray' or both then Mary went to the bedroom.
It is probably not the case that 'Julius is gray' or 'Jeff dropped the apple' or both.
It is certain that 'Julius is gray' or 'Jeff dropped the apple' or both.
It is probably not the case that 'Julius is gray' or 'Jeff dropped the apple' 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.
  0.9::factB.
  0.2::factC.
  %hop1
  0.02::factX:-xor(factC,factB).
  0.02::factY:-and(factC,factA).
  0.02::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Julius is gray' or 'Jeff dropped the apple' or both.