It is highly likely that Sandra is in the kitchen. There is a very good chance that Brian is a rhino. There is almost no chance that Lily is a swan. It is highly likely that if 'Lily is a swan and Sandra is in the kitchen' then Greg is white. It is improbable that if 'Brian is a rhino' or 'Sandra is in the kitchen' or both then Bernhard is yellow. There is almost no chance that if 'Brian is a rhino' or 'Lily is a swan' or both then Mary went to the office.
There is almost no chance that 'Mary went to the office' or 'Greg is white' or both.
There is almost no chance that 'Mary went to the office' or 'Greg is white' or both.
Chances are about even that 'Mary went to the office' or 'Greg is white' 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
  0.9::factA.
  0.8::factB.
  0.02::factC.
  %hop1
  0.9::factX:-and(factC,factA).
  0.1::factY:-or(factB,factA).
  0.02::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Mary went to the office' or 'Greg is white' or both.