We doubt that Mary dropped the apple. It is certain that John picked up the milk. It is improbable that Fred is in the cinema. It is probably the case that if 'John picked up the milk' or 'Fred is in the cinema' or both then Jason is tired. It is probably the case that if either 'John picked up the milk' or 'Mary dropped the apple' but not both then Julius is a rhino. It is likely that if either 'John picked up the milk' or 'Fred is in the cinema' but not both then Brian is yellow.
It is certain that 'Fred is in the cinema' or 'John picked up the milk' or both.
It is certain that 'Fred is in the cinema' or 'John picked up the milk' or both.
There is almost no chance that 'Fred is in the cinema' or 'John 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
  0.2::factA.
  1.0::factB.
  0.1::factC.
  %hop1
  0.7::factX:-or(factB,factC).
  0.7::factY:-xor(factB,factA).
  0.7::factZ:-xor(factB,factC).

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

  query(conclusion).
  
'Fred is in the cinema' or 'John picked up the milk' or both.