There is little chance that Julius is yellow. There is little chance that Fred left the apple. It is unlikely that John went to the office. We doubt that if 'Julius is yellow and John went to the office' then Lily is a lion. It is improbable that if either 'John went to the office' or 'Fred left the apple' but not both then Mary dropped the milk. It is probably not the case that if 'Fred left the apple and John went to the office' then Greg is a rhino.
Chances are slight that 'Mary dropped the milk' or 'Julius is yellow' or both.
Chances are slight that 'Mary dropped the milk' or 'Julius is yellow' or both.
It is almost certain that 'Mary dropped the milk' or 'Julius is yellow' 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
  0.1::factA.
  0.1::factB.
  0.2::factC.
  %hop1
  0.2::factX:-and(factA,factC).
  0.1::factY:-xor(factC,factB).
  0.25::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Mary dropped the milk' or 'Julius is yellow' or both.