Chances are about even that John left the milk. There is little chance that Sumit is thirsty. There is little chance that Emily is a wolf. It is improbable that if 'Emily is a wolf and Sumit is thirsty' then Bernhard is green. It is likely that if 'Sumit is thirsty' or 'Emily is a wolf' or both then Lily is white. There is little chance that if 'Emily is a wolf and Sumit is thirsty' then Greg is gray.
There is a very good chance that 'Sumit is thirsty and Bernhard is green'.
It is impossible that 'Sumit is thirsty and Bernhard is green'.
There is a very good chance that 'Sumit is thirsty 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
  0.5::factA.
  0.1::factB.
  0.1::factC.
  %hop1
  0.1::factX:-and(factC,factB).
  0.7::factY:-or(factB,factC).
  0.1::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Sumit is thirsty and Bernhard is green'.