12．15．Bill worked in a restaurant two miles away from his home． 16．When a new gangster （匪徒） movie came out，Bill would watch it many times． 17．Bill had a large collection of gangster videos at home． 18．Bill made the gun himself and practised shooting in the club． 19．Bill dropped his gun mainly because of his poor eyesight 20．From the passage we learn Bill hurt his knee with his gun in the end．
