There is little chance that Lily is a swan. There is a better than even chance that Sandra took the football. We doubt that Julius is white. There is little chance that if either 'Lily is a swan' or 'Sandra took the football' but not both then Fred dropped the apple. There is little chance that if 'Sandra took the football and Lily is a swan' then Mary grabbed the milk. It is highly unlikely that if either 'Lily is a swan' or 'Julius is white' but not both then Jessica is a sheep.
It is probable that 'Jessica is a sheep and Lily is a swan'.
It is impossible that 'Jessica is a sheep and Lily is a swan'.
It is probable that 'Jessica is a sheep and Lily is a swan'.

  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
  0.1::factA.
  0.6::factB.
  0.2::factC.
  %hop1
  0.1::factX:-xor(factA,factB).
  0.1::factY:-and(factB,factA).
  0.05::factZ:-xor(factA,factC).

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

  query(conclusion).
  
'Jessica is a sheep and Lily is a swan'.