It is highly unlikely that John put down the apple. It is probably the case that Lily is a frog. It is probably the case that Brian is a lion. It is highly unlikely that if 'Brian is a lion' or 'John put down the apple' or both then Greg is yellow. Chances are about even that if 'Lily is a frog and John put down the apple' then Jessica is a mouse. We believe that if either 'John put down the apple' or 'Lily is a frog' but not both then Mary went to the office.
It is probable that 'Mary went to the office' or 'Lily is a frog' or both.
It is probable that 'Mary went to the office' or 'Lily is a frog' or both.
It is improbable that 'Mary went to the office' or 'Lily is a frog' 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
  0.05::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.05::factX:-or(factC,factA).
  0.5::factY:-and(factB,factA).
  0.75::factZ:-xor(factA,factB).

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

  query(conclusion).
  
'Mary went to the office' or 'Lily is a frog' or both.