It is probably the case that John moved to the office. It is highly likely that Gertrude is a sheep. It is probable that Bernhard is a frog. Chances are about even that if either 'John moved to the office' or 'Gertrude is a sheep' but not both then Lily is a lion. We believe that if 'Bernhard is a frog' or 'John moved to the office' or both then Mary went to the garden. It is likely that if either 'Bernhard is a frog' or 'Gertrude is a sheep' but not both then Greg is gray.
It is probably not the case that 'Mary went to the garden' or 'Gertrude is a sheep' or both.
It is almost certain that 'Mary went to the garden' or 'Gertrude is a sheep' or both.
It is probably not the case that 'Mary went to the garden' or 'Gertrude is a sheep' 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.
  0.9::factB.
  0.7::factC.
  %hop1
  0.5::factX:-xor(factA,factB).
  0.75::factY:-or(factC,factA).
  0.7::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Mary went to the garden' or 'Gertrude is a sheep' or both.