It is impossible that Greg is a rhino. We doubt that Mary went to the bedroom. It is highly likely that Bernhard is a swan. It is improbable that if either 'Mary went to the bedroom' or 'Greg is a rhino' but not both then Emily is a wolf. There is almost no chance that if 'Bernhard is a swan' or 'Mary went to the bedroom' or both then Brian is white. It is probable that if 'Bernhard is a swan and Greg is a rhino' then John dropped the apple.
There is almost no chance that 'Emily is a wolf' or 'Greg is a rhino' or both.
There is almost no chance that 'Emily is a wolf' or 'Greg is a rhino' or both.
It is highly likely that 'Emily is a wolf' or 'Greg is a rhino' 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
  0.0::factA.
  0.2::factB.
  0.9::factC.
  %hop1
  0.1::factX:-xor(factB,factA).
  0.02::factY:-or(factC,factB).
  0.7::factZ:-and(factC,factA).

  %hop2
  conclusion:-or(factX,factA).

  query(conclusion).
  
'Emily is a wolf' or 'Greg is a rhino' or both.