It is probable that Sandra left the apple. It is probably not the case that Jessica is a mouse. It is certain that Mary moved to the garden. There is a better than even chance that if 'Mary moved to the garden' or 'Sandra left the apple' or both then Emily is a wolf. We doubt that if 'Sandra left the apple' or 'Mary moved to the garden' or both then John went to the office. There is a better than even chance that if either 'Mary moved to the garden' or 'Sandra left the apple' but not both then Lily is a lion.
There is a very good chance that either 'John went to the office' or 'Lily is a lion' but not both.
It is probably not the case that either 'John went to the office' or 'Lily is a lion' but not both.
There is a very good chance that either 'John went to the office' or 'Lily is a lion' 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.
  0.25::factB.
  1.0::factC.
  %hop1
  0.6::factX:-or(factC,factA).
  0.2::factY:-or(factA,factC).
  0.6::factZ:-xor(factC,factA).

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

  query(conclusion).
  
Either 'John went to the office' or 'Lily is a lion' but not both.