A boy was walking with his dog.A policeman came by and asked,"Does that dog have a license?" The boy answered,"He doesn''t need one;he isn''t old enough to drive." An old lady bought three packets of mothballs and came back to the shop the next morning. "Six more packets of mothballs,please,"she said. The assistant looked surprised."you must have a lot of moths." "yes,"replied the old lady ."I''ve spent a whole day tossing these things at them,but I''ve only hit one so far."