diff --git a/my_game.py b/my_game.py
index 6210110..1dc5ecb 100644
--- a/my_game.py
+++ b/my_game.py
@@ -2,7 +2,7 @@ import pygame
 from pygame import locals
 import random
 pygame.init()  # 初始化
-group = pygame.sprite.Group()
+
 class Books(pygame.sprite.Sprite):
     def __init__(self,image1,image2,image3):
         super().__init__()
@@ -34,12 +34,11 @@ beijing_x = 0
 time = 0
 jump = "running"
 obstacle=Books(stone,cacti,apple)
-
+group = pygame.sprite.Group()
 while True:
     for event in pygame.event.get():
         if event.type == locals.QUIT:
-            # 接收到退出事件后退出程序
-            exit()
+            exit()                    # 接收到退出事件后退出程序
         if event.type == locals.KEYDOWN:
             if jump == "running":
                 if  event.key == locals.K_SPACE:
@@ -82,7 +81,20 @@ while True:
     #else:
     #    obstacle.rect.x -= 8
     #screen.blit(obstacle.image,(obstacle.rect.x, obstacle.rect.y))
-
+    
+    
+    time += 1
+    if time >= 60:
+        time = 0
+        time1 = random.randint(0,50)
+        if time1 > 20:
+            obstacle = Books(stone,cacti,apple)
+            group.add(obstacle)
+    for sprite in group:
+        sprite.rect.x -= 8
+        screen.blit(sprite.image,(sprite.rect.x, sprite.rect.y))
+        if sprite.rect.x <=0-sprite.rect.width:
+            sprite.kill()
     # 刷新画面
     pygame.display.update()
     FPS.tick(60)
\ No newline at end of file