We doubt that John picked up the apple. There is almost no chance that Greg is a lion. Chances are about even that Mary went to the office. Chances are slight that if 'Mary went to the office' or 'Greg is a lion' or both then Fred left the football. It is highly likely that if either 'Greg is a lion' or 'Mary went to the office' but not both then Julius is a swan. It is probable that if either 'Mary went to the office' or 'Greg is a lion' but not both then Lily is a swan.
It is probably not the case that 'Mary went to the office and Lily is a swan'.
It is probably not the case that 'Mary went to the office and Lily is a swan'.
It is likely that 'Mary went to the office and Lily is a swan'.

  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
  0.2::factA.
  0.02::factB.
  0.5::factC.
  %hop1
  0.1::factX:-or(factC,factB).
  0.9::factY:-xor(factB,factC).
  0.7::factZ:-xor(factC,factB).

  %hop2
  conclusion:-and(factC,factZ).

  query(conclusion).
  
'Mary went to the office and Lily is a swan'.