There is almost no chance that Fred is in the office. There is little chance that Mary dropped the apple. There is a very good chance that Julius is a swan. It is highly likely that if either 'Julius is a swan' or 'Mary dropped the apple' but not both then John moved to the garden. We believe that if 'Fred is in the office and Julius is a swan' then Brian is green. It is probably the case that if 'Fred is in the office' or 'Mary dropped the apple' or both then Jessica is a mouse.
There is almost no chance that 'Brian is green and Julius is a swan'.
There is almost no chance that 'Brian is green and Julius is a swan'.
There is a better than even chance that 'Brian is green and Julius is a swan'.

  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
  0.02::factA.
  0.1::factB.
  0.8::factC.
  %hop1
  0.9::factX:-xor(factC,factB).
  0.75::factY:-and(factA,factC).
  0.7::factZ:-or(factA,factB).

  %hop2
  conclusion:-and(factY,factC).

  query(conclusion).
  
'Brian is green and Julius is a swan'.