Chances are slight that Mary went to the office. Chances are slight that Bernhard is a swan. It is highly likely that Greg is a frog. It is likely that if 'Mary went to the office and Bernhard is a swan' then Daniel got the milk. It is highly unlikely that if either 'Mary went to the office' or 'Bernhard is a swan' but not both then Sandra dropped the apple. There is little chance that if 'Mary went to the office' or 'Greg is a frog' or both then Emily is a wolf.
Chances are slight that 'Emily is a wolf' or 'Daniel got the milk' or both.
Chances are slight that 'Emily is a wolf' or 'Daniel got the milk' or both.
It is highly likely that 'Emily is a wolf' or 'Daniel got the milk' 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
  0.1::factA.
  0.1::factB.
  0.9::factC.
  %hop1
  0.7::factX:-and(factA,factB).
  0.05::factY:-xor(factA,factB).
  0.1::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Emily is a wolf' or 'Daniel got the milk' or both.