There is almost no chance that Daniel put down the milk. It is probably the case that Sandra dropped the apple. It is highly unlikely that Mary left the football. There is a very good chance that if 'Mary left the football and Daniel put down the milk' then Gertrude is a cat. It is probably not the case that if 'Sandra dropped the apple' or 'Daniel put down the milk' or both then Brian is green. There is a better than even chance that if either 'Sandra dropped the apple' or 'Mary left the football' but not both then Julius is yellow.
There is a very good chance that 'Mary left the football' or 'Brian is green' or both.
It is unlikely that 'Mary left the football' or 'Brian is green' or both.
There is a very good chance that 'Mary left the football' or 'Brian is green' or 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
  0.02::factA.
  0.7::factB.
  0.05::factC.
  %hop1
  0.8::factX:-and(factC,factA).
  0.25::factY:-or(factB,factA).
  0.6::factZ:-xor(factB,factC).

  %hop2
  conclusion:-or(factC,factY).

  query(conclusion).
  
'Mary left the football' or 'Brian is green' or both.