It is likely that John dropped the apple. It is certain that Mary picked up the milk. It is highly unlikely that Lily is yellow. It is probably the case that if 'John dropped the apple and Lily is yellow' then Winona is a wolf. It is improbable that if 'Lily is yellow and John dropped the apple' then Brian is a swan. It is probably the case that if 'John dropped the apple' or 'Lily is yellow' or both then Greg is a lion.
Chances are about even that 'John dropped the apple' or 'Mary picked up the milk' or both.
It is certain that 'John dropped the apple' or 'Mary picked up the milk' or both.
Chances are about even that 'John dropped the apple' or 'Mary picked up the milk' 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.
  1.0::factB.
  0.05::factC.
  %hop1
  0.7::factX:-and(factA,factC).
  0.1::factY:-and(factC,factA).
  0.7::factZ:-or(factA,factC).

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

  query(conclusion).
  
'John dropped the apple' or 'Mary picked up the milk' or both.