更新 'Alien_Invasion.py'

Alien_Invasion.py

@@ -1,8 +1,15 @@
 import sys
+from time import sleep
+
 import pygame
 
 from settings import Settings
+from game_stats import GameStats
+from scoreboard import Scoreboard
+from button import Button
 from ship import Ship
+from bullet import Bullet
+from alien import Alien
 
 class AlienInvasion: # 管理游戏资源和行为的类11