It is probably the case that Julius is white. It is impossible that Sandra left the milk. It is likely that Brian is gray. It is unlikely that if 'Julius is white' or 'Sandra left the milk' or both then Daniel put down the milk. It is almost certain that if 'Brian is gray and Sandra left the milk' then Mary went to the office. It is probable that if 'Brian is gray and Julius is white' then John discarded the apple.
It is likely that 'Brian is gray' or 'John discarded the apple' or both.
It is likely that 'Brian is gray' or 'John discarded the apple' or both.
There is almost no chance that 'Brian is gray' or 'John discarded the apple' 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.
  0.0::factB.
  0.7::factC.
  %hop1
  0.2::factX:-or(factA,factB).
  0.95::factY:-and(factC,factB).
  0.7::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Brian is gray' or 'John discarded the apple' or both.