There is almost no chance that Sandra dropped the apple. It is probable that Julius is gray. We doubt that Mary moved to the garden. There is a very good chance that if 'Sandra dropped the apple and Julius is gray' then John took the football. It is probable that if 'Mary moved to the garden and Sandra dropped the apple' then Lily is a lion. There is almost no chance that if either 'Julius is gray' or 'Sandra dropped the apple' but not both then Brian is a frog.
There is almost no chance that 'John took the football' or 'Sandra dropped the apple' or both.
There is almost no chance that 'John took the football' or 'Sandra dropped the apple' or both.
It is probable that 'John took the football' or 'Sandra dropped the apple' 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.
  0.7::factB.
  0.2::factC.
  %hop1
  0.8::factX:-and(factA,factB).
  0.7::factY:-and(factC,factA).
  0.02::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'John took the football' or 'Sandra dropped the apple' or both.