It is almost certain that Emily is a mouse. There is almost no chance that Lily is white. There is a better than even chance that Mary went to the office. It is probable that if 'Mary went to the office and Lily is white' then Greg is green. It is highly likely that if 'Emily is a mouse and Mary went to the office' then Bernhard is a frog. It is highly unlikely that if either 'Emily is a mouse' or 'Lily is white' but not both then Julius is a lion.
It is impossible that either 'Emily is a mouse' or 'Mary went to the office' but not both.
Chances are about even that either 'Emily is a mouse' or 'Mary went to the office' but not both.
It is impossible that either 'Emily is a mouse' or 'Mary went to the office' 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
  0.95::factA.
  0.02::factB.
  0.6::factC.
  %hop1
  0.7::factX:-and(factC,factB).
  0.9::factY:-and(factA,factC).
  0.05::factZ:-xor(factA,factB).

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

  query(conclusion).
  
Either 'Emily is a mouse' or 'Mary went to the office' but not both.