It is probably the case that Bernhard is a frog. It is improbable that Lily is green. We believe that Greg is white. There is almost no chance that if 'Bernhard is a frog and Lily is green' then Gertrude is a cat. It is likely that if 'Bernhard is a frog' or 'Lily is green' or both then John dropped the apple. It is probable that if 'Lily is green and Bernhard is a frog' then Mary left the milk.
Chances are about even that 'Mary left the milk' or 'John dropped the apple' or both.
Chances are about even that 'Mary left the milk' or 'John dropped the apple' or both.
It is almost certain that 'Mary left the milk' or 'John dropped the apple' 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
  0.7::factA.
  0.1::factB.
  0.75::factC.
  %hop1
  0.02::factX:-and(factA,factB).
  0.7::factY:-or(factA,factB).
  0.7::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Mary left the milk' or 'John dropped the apple' or both.