There is a better than even chance that Mary left the football. It is highly likely that Jessica is a mouse. It is impossible that Greg is white. It is almost certain that if 'Jessica is a mouse' or 'Greg is white' or both then Bernhard is a swan. It is certain that if either 'Jessica is a mouse' or 'Mary left the football' but not both then Lily is a rhino. It is highly unlikely that if either 'Greg is white' or 'Mary left the football' but not both then Julius is a frog.
It is impossible that 'Greg is white and Jessica is a mouse'.
It is impossible that 'Greg is white and Jessica is a mouse'.
Chances are about even that 'Greg is white and Jessica is a mouse'.

  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
  0.6::factA.
  0.9::factB.
  0.0::factC.
  %hop1
  0.95::factX:-or(factB,factC).
  1.0::factY:-xor(factB,factA).
  0.05::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Greg is white and Jessica is a mouse'.