There is almost no chance that Greg is yellow. It is almost certain that Gertrude is a sheep. Chances are about even that John took the football. We doubt that if either 'Gertrude is a sheep' or 'Greg is yellow' but not both then Emily is a mouse. We doubt that if 'John took the football and Greg is yellow' then Julius is a frog. It is probable that if 'Gertrude is a sheep and Greg is yellow' then Brian is a lion.
It is almost certain that 'Gertrude is a sheep' or 'Emily is a mouse' or both.
It is almost certain that 'Gertrude is a sheep' or 'Emily is a mouse' or both.
It is unlikely that 'Gertrude is a sheep' or 'Emily is a mouse' 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
  0.02::factA.
  0.95::factB.
  0.5::factC.
  %hop1
  0.2::factX:-xor(factB,factA).
  0.2::factY:-and(factC,factA).
  0.7::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Gertrude is a sheep' or 'Emily is a mouse' or both.