It is highly likely that Julius is yellow. There is almost no chance that Daniel got the apple. It is highly unlikely that Sandra left the milk. Chances are about even that if 'Daniel got the apple' or 'Sandra left the milk' or both then Brian is a frog. It is probable that if either 'Julius is yellow' or 'Daniel got the apple' but not both then Mary grabbed the milk. It is unlikely that if either 'Sandra left the milk' or 'Daniel got the apple' but not both then Greg is a rhino.
It is impossible that 'Mary grabbed the milk' or 'Sandra left the milk' or both.
There is a better than even chance that 'Mary grabbed the milk' or 'Sandra left the milk' or both.
It is impossible that 'Mary grabbed the milk' or 'Sandra left the milk' 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
  0.9::factA.
  0.02::factB.
  0.05::factC.
  %hop1
  0.5::factX:-or(factB,factC).
  0.7::factY:-xor(factA,factB).
  0.2::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Mary grabbed the milk' or 'Sandra left the milk' or both.