We believe that Bernhard is a rhino. It is likely that Greg is a swan. It is unlikely that Mary went to the office. It is probable that if 'Greg is a swan and Bernhard is a rhino' then Antoine is hungry. It is improbable that if 'Mary went to the office and Bernhard is a rhino' then John left the milk. It is highly unlikely that if 'Greg is a swan' or 'Bernhard is a rhino' or both then Lily is yellow.
There is a very good chance that 'Mary went to the office and John left the milk'.
There is almost no chance that 'Mary went to the office and John left the milk'.
There is a very good chance that 'Mary went to the office and John left 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
  0.75::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.7::factX:-and(factB,factA).
  0.1::factY:-and(factC,factA).
  0.05::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Mary went to the office and John left the milk'.