It is impossible that Emily is a mouse. It is probable that Greg is a rhino. There is little chance that Sandra got the milk. It is probable that if 'Emily is a mouse' or 'Greg is a rhino' or both then Julius is a lion. It is probably not the case that if either 'Emily is a mouse' or 'Greg is a rhino' but not both then Mary went to the hallway. Chances are slight that if 'Greg is a rhino' or 'Sandra got the milk' or both then Bernhard is a swan.
It is probably the case that either 'Sandra got the milk' or 'Greg is a rhino' but not both.
It is probably the case that either 'Sandra got the milk' or 'Greg is a rhino' but not both.
Chances are slight that either 'Sandra got the milk' or 'Greg is a rhino' 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
  0.0::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.7::factX:-or(factA,factB).
  0.25::factY:-xor(factA,factB).
  0.1::factZ:-or(factB,factC).

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

  query(conclusion).
  
Either 'Sandra got the milk' or 'Greg is a rhino' but not both.