Chances are slight that Daniel left the apple. It is impossible that Greg is a rhino. It is impossible that Mary went to the office. There is almost no chance that if 'Greg is a rhino' or 'Daniel left the apple' or both then Julius is gray. It is highly likely that if either 'Mary went to the office' or 'Greg is a rhino' but not both then Sandra dropped the milk. It is highly likely that if 'Greg is a rhino and Mary went to the office' then Brian is a swan.
There is a better than even chance that 'Julius is gray and Sandra dropped the milk'.
It is impossible that 'Julius is gray and Sandra dropped the milk'.
There is a better than even chance that 'Julius is gray and Sandra dropped the milk'.

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

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

  query(conclusion).
  
'Julius is gray and Sandra dropped the milk'.