There is a better than even chance that John put down the milk. It is probable that Julius is a frog. It is likely that Jessica is a mouse. There is little chance that if 'Julius is a frog' or 'John put down the milk' or both then Sandra dropped the apple. It is highly unlikely that if either 'Julius is a frog' or 'John put down the milk' but not both then Mary went to the kitchen. Chances are about even that if 'Jessica is a mouse and John put down the milk' then Lily is white.
There is almost no chance that 'Jessica is a mouse' or 'Lily is white' or both.
It is probably the case that 'Jessica is a mouse' or 'Lily is white' or both.
There is almost no chance that 'Jessica is a mouse' or 'Lily is white' 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.
  0.7::factB.
  0.7::factC.
  %hop1
  0.1::factX:-or(factB,factA).
  0.05::factY:-xor(factB,factA).
  0.5::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Jessica is a mouse' or 'Lily is white' or both.