We doubt that Bernhard is yellow. It is probable that Fred discarded the apple. It is improbable that John got the milk. We believe that if 'John got the milk and Bernhard is yellow' then Bill went to the bedroom. It is probable that if 'Bernhard is yellow and John got the milk' then Julius is gray. It is improbable that if 'Fred discarded the apple' or 'John got the milk' or both then Mary left the football.
There is almost no chance that 'John got the milk and Mary left the football'.
There is almost no chance that 'John got the milk and Mary left the football'.
There is a better than even chance that 'John got the milk and Mary left the football'.

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

  %hop2
  conclusion:-and(factC,factZ).

  query(conclusion).
  
'John got the milk and Mary left the football'.