There is a very good chance that Sandra left the milk. It is probably the case that Lily is green. It is unlikely that Yann is bored. There is almost no chance that if 'Lily is green' or 'Yann is bored' or both then Jeff moved to the garden. It is highly likely that if 'Lily is green and Sandra left the milk' then Mary went to the bedroom. It is unlikely that if 'Yann is bored' or 'Sandra left the milk' or both then John dropped the apple.
There is a better than even chance that 'Lily is green and Sandra left the milk'.
There is a better than even chance that 'Lily is green and Sandra left the milk'.
There is little chance that 'Lily is green and Sandra left the milk'.

  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
  0.8::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.02::factX:-or(factB,factC).
  0.9::factY:-and(factB,factA).
  0.2::factZ:-or(factC,factA).

  %hop2
  conclusion:-and(factB,factA).

  query(conclusion).
  
'Lily is green and Sandra left the milk'.