It is unlikely that Greg is a lion. It is probably the case that Brian is a rhino. It is certain that Daniel took the football. It is probably the case that if 'Greg is a lion and Daniel took the football' then John got the milk. It is improbable that if 'Daniel took the football' or 'Brian is a rhino' or both then Julius is a swan. It is unlikely that if 'Greg is a lion' or 'Brian is a rhino' or both then Mary went to the hallway.
There is almost no chance that 'Julius is a swan and Mary went to the hallway'.
There is almost no chance that 'Julius is a swan and Mary went to the hallway'.
It is probably the case that 'Julius is a swan and Mary went to the hallway'.

  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
  0.2::factA.
  0.7::factB.
  1.0::factC.
  %hop1
  0.7::factX:-and(factA,factC).
  0.1::factY:-or(factC,factB).
  0.2::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Julius is a swan and Mary went to the hallway'.