Chances are slight that Greg is a rhino. It is improbable that Sandra left the milk. It is probably the case that Brian is a swan. There is a very good chance that if 'Sandra left the milk and Brian is a swan' then Bernhard is green. It is highly likely that if either 'Sandra left the milk' or 'Brian is a swan' but not both then Bill went to the office. It is certain that if 'Sandra left the milk and Brian is a swan' then Jason is bored.
It is certain that 'Sandra left the milk and Bernhard is green'.
It is highly unlikely that 'Sandra left the milk and Bernhard is green'.
It is certain that 'Sandra left the milk and Bernhard is green'.

  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.
  0.1::factB.
  0.7::factC.
  %hop1
  0.8::factX:-and(factB,factC).
  0.9::factY:-xor(factB,factC).
  1.0::factZ:-and(factB,factC).

  %hop2
  conclusion:-and(factB,factX).

  query(conclusion).
  
'Sandra left the milk and Bernhard is green'.