There is almost no chance that Julius is a frog. There is a very good chance that Jessica is a cat. We believe that Mary went to the office. Chances are about even that if 'Julius is a frog' or 'Jessica is a cat' or both then Emily is a sheep. It is impossible that if 'Mary went to the office' or 'Julius is a frog' or both then Greg is a swan. It is certain that if 'Julius is a frog and Mary went to the office' then Sandra dropped the apple.
It is probably the case that 'Mary went to the office and Emily is a sheep'.
It is probably not the case that 'Mary went to the office and Emily is a sheep'.
It is probably the case that 'Mary went to the office and Emily is a sheep'.

  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.
  0.8::factB.
  0.75::factC.
  %hop1
  0.5::factX:-or(factA,factB).
  0.0::factY:-or(factC,factA).
  1.0::factZ:-and(factA,factC).

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

  query(conclusion).
  
'Mary went to the office and Emily is a sheep'.