Chances are about even that Sandra dropped the milk. It is unlikely that Fred went to the garden. It is certain that John got the apple. It is improbable that if 'Sandra dropped the milk' or 'John got the apple' or both then Mary left the football. It is impossible that if 'Sandra dropped the milk and John got the apple' then Lily is green. There is little chance that if either 'Sandra dropped the milk' or 'John got the apple' but not both then Bernhard is a frog.
It is likely that 'Mary left the football and John got the apple'.
There is little chance that 'Mary left the football and John got the apple'.
It is likely that 'Mary left the football and John got the apple'.

  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.
  0.2::factB.
  1.0::factC.
  %hop1
  0.1::factX:-or(factA,factC).
  0.0::factY:-and(factA,factC).
  0.1::factZ:-xor(factA,factC).

  %hop2
  conclusion:-and(factX,factC).

  query(conclusion).
  
'Mary left the football and John got the apple'.