It is probably the case that John took the apple. There is almost no chance that Julius is a swan. Chances are slight that Brian is a rhino. There is little chance that if either 'Julius is a swan' or 'John took the apple' but not both then Sandra dropped the milk. It is highly likely that if 'Brian is a rhino' or 'John took the apple' or both then Greg is gray. There is a very good chance that if 'Brian is a rhino and John took the apple' then Mary went to the hallway.
It is probable that 'Brian is a rhino' or 'Julius is a swan' or both.
Chances are slight that 'Brian is a rhino' or 'Julius is a swan' or both.
It is probable that 'Brian is a rhino' or 'Julius is a swan' 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.
  0.02::factB.
  0.1::factC.
  %hop1
  0.1::factX:-xor(factB,factA).
  0.9::factY:-or(factC,factA).
  0.8::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Brian is a rhino' or 'Julius is a swan' or both.