It is probably the case that Julius is a frog. It is probably the case that Brian is a lion. It is likely that John picked up the apple. It is probable that if 'John picked up the apple' or 'Julius is a frog' or both then Lily is a rhino. We doubt that if 'Brian is a lion' or 'John picked up the apple' or both then Mary is in the school. It is highly likely that if either 'Brian is a lion' or 'Julius is a frog' but not both then Winona is a mouse.
It is highly unlikely that 'Winona is a mouse' or 'John picked up the apple' or both.
There is a very good chance that 'Winona is a mouse' or 'John picked up the apple' or both.
It is highly unlikely that 'Winona is a mouse' or 'John picked up the apple' 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.
  0.7::factB.
  0.7::factC.
  %hop1
  0.7::factX:-or(factC,factA).
  0.2::factY:-or(factB,factC).
  0.9::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Winona is a mouse' or 'John picked up the apple' or both.