It is probable that Jessica is a mouse. There is a better than even chance that Julius is a rhino. There is little chance that Sandra left the football. It is improbable that if 'Julius is a rhino' or 'Sandra left the football' or both then John went to the office. It is unlikely that if either 'Sandra left the football' or 'Jessica is a mouse' but not both then Mary got the milk. There is almost no chance that if 'Jessica is a mouse' or 'Julius is a rhino' or both then Brian is a swan.
It is highly unlikely that 'Jessica is a mouse' or 'Sandra left the football' or both.
We believe that 'Jessica is a mouse' or 'Sandra left the football' or both.
It is highly unlikely that 'Jessica is a mouse' or 'Sandra left the football' 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
  0.7::factA.
  0.6::factB.
  0.1::factC.
  %hop1
  0.1::factX:-or(factB,factC).
  0.2::factY:-xor(factC,factA).
  0.02::factZ:-or(factA,factB).

  %hop2
  conclusion:-or(factA,factC).

  query(conclusion).
  
'Jessica is a mouse' or 'Sandra left the football' or both.