It is certain that Brian is a rhino. It is highly likely that Bernhard is green. It is unlikely that John left the football. It is unlikely that if either 'John left the football' or 'Brian is a rhino' but not both then Greg is yellow. It is improbable that if 'Brian is a rhino and John left the football' then Julius is a frog. It is almost certain that if either 'Bernhard is green' or 'Brian is a rhino' but not both then Lily is a lion.
It is certain that 'Bernhard is green' or 'Brian is a rhino' or both.
It is certain that 'Bernhard is green' or 'Brian is a rhino' or both.
There is little chance that 'Bernhard is green' or 'Brian is a rhino' 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
  1.0::factA.
  0.9::factB.
  0.2::factC.
  %hop1
  0.2::factX:-xor(factC,factA).
  0.1::factY:-and(factA,factC).
  0.95::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Bernhard is green' or 'Brian is a rhino' or both.