Chances are about even that Mary went to the office. There is little chance that John left the football. It is probably the case that Antoine is hungry. It is unlikely that if 'Mary went to the office' or 'Antoine is hungry' or both then Gertrude is a sheep. There is a better than even chance that if 'Antoine is hungry and John left the football' then Bernhard is green. It is improbable that if 'John left the football and Mary went to the office' then Greg is a lion.
There is a better than even chance that 'Mary went to the office' or 'John left the football' or both.
There is a better than even chance that 'Mary went to the office' or 'John left the football' or both.
There is little chance that 'Mary went to the office' or 'John left the football' 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
  0.5::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.2::factX:-or(factA,factC).
  0.6::factY:-and(factC,factB).
  0.1::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Mary went to the office' or 'John left the football' or both.