It is almost certain that Julius is a frog. It is likely that Winona is a sheep. It is unlikely that John moved to the office. It is improbable that if 'Julius is a frog' or 'Winona is a sheep' or both then Mary grabbed the milk. Chances are slight that if either 'Winona is a sheep' or 'John moved to the office' but not both then Yann is hungry. It is highly unlikely that if 'Julius is a frog' or 'John moved to the office' or both then Greg is a swan.
It is impossible that 'Mary grabbed the milk and Greg is a swan'.
It is impossible that 'Mary grabbed the milk and Greg is a swan'.
Chances are about even that 'Mary grabbed the milk and Greg is a swan'.

  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
  0.95::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.1::factX:-or(factA,factB).
  0.1::factY:-xor(factB,factC).
  0.05::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Mary grabbed the milk and Greg is a swan'.