There is a better than even chance that Jessica is a mouse. It is highly likely that Brian is a swan. It is probably the case that Yann is hungry. We doubt that if 'Jessica is a mouse and Yann is hungry' then Greg is a frog. Chances are about even that if either 'Brian is a swan' or 'Yann is hungry' but not both then John went to the hallway. It is highly unlikely that if 'Yann is hungry and Jessica is a mouse' then Sandra got the football.
It is highly likely that 'Sandra got the football' or 'Brian is a swan' or both.
It is highly likely that 'Sandra got the football' or 'Brian is a swan' or both.
It is probably not the case that 'Sandra got the football' or 'Brian is a swan' 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
  0.6::factA.
  0.9::factB.
  0.7::factC.
  %hop1
  0.2::factX:-and(factA,factC).
  0.5::factY:-xor(factB,factC).
  0.05::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Sandra got the football' or 'Brian is a swan' or both.