Chances are about even that Fred went to the garden. There is a better than even chance that Sandra dropped the milk. It is likely that Bernhard is gray. It is likely that if 'Sandra dropped the milk' or 'Fred went to the garden' or both then Mary took the football. It is improbable that if 'Fred went to the garden' or 'Sandra dropped the milk' or both then John moved to the office. It is likely that if 'Sandra dropped the milk and Bernhard is gray' then Julius is a frog.
Chances are about even that 'Fred went to the garden' or 'John moved to the office' or both.
Chances are about even that 'Fred went to the garden' or 'John moved to the office' or both.
It is impossible that 'Fred went to the garden' or 'John moved to the office' 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
  0.5::factA.
  0.6::factB.
  0.7::factC.
  %hop1
  0.7::factX:-or(factB,factA).
  0.1::factY:-or(factA,factB).
  0.7::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Fred went to the garden' or 'John moved to the office' or both.