There is almost no chance that Lily is a lion. There is little chance that Fred went to the garden. It is certain that Greg is gray. It is likely that if 'Greg is gray' or 'Lily is a lion' or both then Julius is a swan. There is a very good chance that if either 'Fred went to the garden' or 'Lily is a lion' but not both then John took the apple. There is little chance that if 'Greg is gray and Lily is a lion' then Sandra got the milk.
There is a very good chance that 'Fred went to the garden and Sandra got the milk'.
It is impossible that 'Fred went to the garden and Sandra got the milk'.
There is a very good chance that 'Fred went to the garden and Sandra got 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
  0.02::factA.
  0.1::factB.
  1.0::factC.
  %hop1
  0.7::factX:-or(factC,factA).
  0.8::factY:-xor(factB,factA).
  0.1::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Fred went to the garden and Sandra got the milk'.