There is almost no chance that Brian is a lion. Chances are about even that Julius is a swan. We doubt that Bill went to the office. There is a very good chance that if 'Brian is a lion and Julius is a swan' then Daniel got the milk. It is improbable that if 'Brian is a lion' or 'Bill went to the office' or both then Lily is gray. It is improbable that if either 'Bill went to the office' or 'Julius is a swan' but not both then Greg is a rhino.
It is almost certain that 'Greg is a rhino and Lily is gray'.
It is impossible that 'Greg is a rhino and Lily is gray'.
It is almost certain that 'Greg is a rhino and Lily is gray'.

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

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

  query(conclusion).
  
'Greg is a rhino and Lily is gray'.