It is likely that Brian is yellow. Chances are about even that Julius is white. There is a very good chance that Greg is a rhino. There is little chance that if 'Greg is a rhino and Julius is white' then Winona is a sheep. We doubt that if 'Julius is white and Brian is yellow' then Lily is a frog. It is probably the case that if 'Greg is a rhino and Brian is yellow' then Mary went to the bedroom.
It is highly unlikely that 'Mary went to the bedroom' or 'Lily is a frog' or both.
Chances are about even that 'Mary went to the bedroom' or 'Lily is a frog' or both.
It is highly unlikely that 'Mary went to the bedroom' or 'Lily is a frog' 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.
  0.5::factB.
  0.8::factC.
  %hop1
  0.1::factX:-and(factC,factB).
  0.2::factY:-and(factB,factA).
  0.7::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Mary went to the bedroom' or 'Lily is a frog' or both.