It is likely that Greg is a lion. It is probable that Yann is thirsty. There is little chance that Daniel left the apple. We believe that if 'Daniel left the apple' or 'Yann is thirsty' or both then Julius is a rhino. It is almost certain that if either 'Greg is a lion' or 'Yann is thirsty' but not both then Lily is green. It is certain that if either 'Greg is a lion' or 'Daniel left the apple' but not both then Mary got the football.
It is probable that either 'Mary got the football' or 'Daniel left the apple' but not both.
It is probable that either 'Mary got the football' or 'Daniel left the apple' but not both.
There is almost no chance that either 'Mary got the football' or 'Daniel left the apple' 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
  0.7::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.75::factX:-or(factC,factB).
  0.95::factY:-xor(factA,factB).
  1.0::factZ:-xor(factA,factC).

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

  query(conclusion).
  
Either 'Mary got the football' or 'Daniel left the apple' but not both.