It is probable that Jeff moved to the garden. We doubt that Mary got the football. There is little chance that John discarded the milk. It is certain that if 'John discarded the milk and Mary got the football' then Bernhard is a frog. It is probably the case that if either 'John discarded the milk' or 'Jeff moved to the garden' but not both then Julius is a swan. It is certain that if 'Jeff moved to the garden and John discarded the milk' then Lily is green.
There is little chance that 'Mary got the football' or 'Jeff moved to the garden' or both.
We believe that 'Mary got the football' or 'Jeff moved to the garden' or both.
There is little chance that 'Mary got the football' or 'Jeff moved to the garden' 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.
  0.2::factB.
  0.1::factC.
  %hop1
  1.0::factX:-and(factC,factB).
  0.7::factY:-xor(factC,factA).
  1.0::factZ:-and(factA,factC).

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

  query(conclusion).
  
'Mary got the football' or 'Jeff moved to the garden' or both.