It is likely that Bernhard is white. There is a very good chance that Lily is a frog. We doubt that Greg is a swan. There is almost no chance that if 'Greg is a swan and Bernhard is white' then Bill moved to the office. There is little chance that if 'Greg is a swan and Lily is a frog' then Fred left the football. There is little chance that if 'Lily is a frog' or 'Greg is a swan' or both then Brian is a rhino.
It is probably the case that 'Brian is a rhino and Lily is a frog'.
It is improbable that 'Brian is a rhino and Lily is a frog'.
It is probably the case that 'Brian is a rhino and Lily is a frog'.

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

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

  query(conclusion).
  
'Brian is a rhino and Lily is a frog'.