There is little chance that Lily is yellow. There is little chance that Yann is tired. Chances are slight that Julius is gray. It is likely that if either 'Yann is tired' or 'Lily is yellow' but not both then Mary went to the bedroom. Chances are about even that if either 'Yann is tired' or 'Julius is gray' but not both then Greg is a rhino. It is likely that if 'Julius is gray and Lily is yellow' then Sandra left the milk.
It is certain that 'Greg is a rhino' or 'Sandra left the milk' or both.
Chances are slight that 'Greg is a rhino' or 'Sandra left the milk' or both.
It is certain that 'Greg is a rhino' or 'Sandra left the milk' 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.
  0.1::factC.
  %hop1
  0.7::factX:-xor(factB,factA).
  0.5::factY:-xor(factB,factC).
  0.7::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Greg is a rhino' or 'Sandra left the milk' or both.