There is almost no chance that Lily is a frog. There is a better than even chance that Greg is white. Chances are about even that Winona is a mouse. It is likely that if 'Winona is a mouse' or 'Greg is white' or both then Sandra left the football. Chances are about even that if 'Lily is a frog' or 'Greg is white' or both then Fred went to the garden. It is likely that if 'Greg is white and Lily is a frog' then Brian is yellow.
Chances are about even that either 'Winona is a mouse' or 'Lily is a frog' but not both.
Chances are about even that either 'Winona is a mouse' or 'Lily is a frog' but not both.
It is highly unlikely that either 'Winona is a mouse' or 'Lily is a frog' but not both.

  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.
  0.6::factB.
  0.5::factC.
  %hop1
  0.7::factX:-or(factC,factB).
  0.5::factY:-or(factA,factB).
  0.7::factZ:-and(factB,factA).

  %hop2
  conclusion:-xor(factC,factA).

  query(conclusion).
  
Either 'Winona is a mouse' or 'Lily is a frog' but not both.