Chances are about even that Greg is gray. There is a better than even chance that Daniel grabbed the apple. We believe that Brian is green. It is probably the case that if either 'Brian is green' or 'Daniel grabbed the apple' but not both then Sandra dropped the milk. It is highly likely that if 'Daniel grabbed the apple' or 'Greg is gray' or both then John went to the hallway. There is little chance that if 'Daniel grabbed the apple' or 'Brian is green' or both then Jeff moved to the office.
It is probably the case that either 'Daniel grabbed the apple' or 'Sandra dropped the milk' but not both.
It is probably the case that either 'Daniel grabbed the apple' or 'Sandra dropped the milk' but not both.
It is unlikely that either 'Daniel grabbed the apple' or 'Sandra dropped the milk' 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
  0.5::factA.
  0.6::factB.
  0.75::factC.
  %hop1
  0.7::factX:-xor(factC,factB).
  0.9::factY:-or(factB,factA).
  0.1::factZ:-or(factB,factC).

  %hop2
  conclusion:-xor(factB,factX).

  query(conclusion).
  
Either 'Daniel grabbed the apple' or 'Sandra dropped the milk' but not both.