It is certain that Gertrude is a mouse. It is probably the case that Brian is green. There is little chance that Sandra left the apple. We doubt that if 'Brian is green and Sandra left the apple' then Emily is a wolf. It is almost certain that if either 'Sandra left the apple' or 'Gertrude is a mouse' but not both then Fred dropped the milk. There is little chance that if either 'Gertrude is a mouse' or 'Sandra left the apple' but not both then Greg is a frog.
It is impossible that 'Fred dropped the milk and Emily is a wolf'.
It is impossible that 'Fred dropped the milk and Emily is a wolf'.
Chances are about even that 'Fred dropped the milk and Emily is a wolf'.

  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
  1.0::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.2::factX:-and(factB,factC).
  0.95::factY:-xor(factC,factA).
  0.1::factZ:-xor(factA,factC).

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

  query(conclusion).
  
'Fred dropped the milk and Emily is a wolf'.