It is improbable that Daniel grabbed the milk. There is a better than even chance that Greg is a frog. It is certain that Mary went to the hallway. It is probably not the case that if 'Daniel grabbed the milk and Mary went to the hallway' then Julius is a rhino. It is improbable that if either 'Greg is a frog' or 'Mary went to the hallway' but not both then Lily is a swan. It is highly unlikely that if 'Daniel grabbed the milk and Greg is a frog' then John moved to the garden.
It is improbable that 'Daniel grabbed the milk' or 'Lily is a swan' or both.
It is improbable that 'Daniel grabbed the milk' or 'Lily is a swan' or both.
It is likely that 'Daniel grabbed the milk' or 'Lily is a swan' 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.
  1.0::factC.
  %hop1
  0.25::factX:-and(factA,factC).
  0.1::factY:-xor(factB,factC).
  0.05::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Daniel grabbed the milk' or 'Lily is a swan' or both.