It is probable that Jeff put down the milk. There is a better than even chance that Lily is green. It is probable that Bernhard is gray. It is highly likely that if 'Jeff put down the milk and Lily is green' then Mary moved to the garden. We doubt that if 'Jeff put down the milk' or 'Bernhard is gray' or both then Julius is a swan. We doubt that if 'Jeff put down the milk' or 'Bernhard is gray' or both then Greg is yellow.
It is almost certain that 'Julius is a swan and Jeff put down the milk'.
It is improbable that 'Julius is a swan and Jeff put down the milk'.
It is almost certain that 'Julius is a swan and Jeff put down the milk'.

  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
  0.7::factA.
  0.6::factB.
  0.7::factC.
  %hop1
  0.9::factX:-and(factA,factB).
  0.2::factY:-or(factA,factC).
  0.2::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Julius is a swan and Jeff put down the milk'.