It is highly likely that Lily is green. Chances are about even that Jeff went to the bedroom. It is probable that Fred put down the apple. We doubt that if 'Fred put down the apple and Lily is green' then Sandra dropped the milk. We doubt that if either 'Jeff went to the bedroom' or 'Fred put down the apple' but not both then Bernhard is gray. It is improbable that if 'Lily is green' or 'Jeff went to the bedroom' or both then Gertrude is a mouse.
There is a very good chance that 'Fred put down the apple' or 'Jeff went to the bedroom' or both.
There is a very good chance that 'Fred put down the apple' or 'Jeff went to the bedroom' or both.
We doubt that 'Fred put down the apple' or 'Jeff went to the bedroom' 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.
  0.5::factB.
  0.7::factC.
  %hop1
  0.2::factX:-and(factC,factA).
  0.2::factY:-xor(factB,factC).
  0.1::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Fred put down the apple' or 'Jeff went to the bedroom' or both.