It is probably the case that Julius is gray. There is little chance that Mary moved to the garden. It is highly unlikely that Gertrude is a sheep. It is highly likely that if 'Gertrude is a sheep' or 'Julius is gray' or both then Sandra dropped the milk. It is improbable that if 'Mary moved to the garden and Julius is gray' then Brian is a swan. There is almost no chance that if either 'Mary moved to the garden' or 'Julius is gray' but not both then Daniel took the apple.
It is impossible that 'Daniel took the apple and Brian is a swan'.
It is impossible that 'Daniel took the apple and Brian is a swan'.
There is a better than even chance that 'Daniel took the apple and Brian is a swan'.

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

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

  query(conclusion).
  
'Daniel took the apple and Brian is a swan'.