diff --git a/my_game.py b/my_game.py
index 7cca968..6887950 100644
--- a/my_game.py
+++ b/my_game.py
@@ -12,7 +12,7 @@ class Block(pygame.sprite.Sprite):
         self.rect.y=500-self.rect.height
 screen = pygame.display.set_mode((1000, 600))
 FPS = pygame.time.Clock()  # pygame时钟，控制游戏速度（帧数）
-
+zaw_list=pygame.sprite.Group()
 # 载入图片
 background = pygame.image.load('bg.png')    # 背景
 road = pygame.image.load('road.png')      # 路
@@ -35,7 +35,7 @@ y=400
 #z=random.choice([stone,cacti,apple])
 #rect=stone.get_rect()
 #z_x=1000
-
+time=0
 road_x=0
 bg_x=0
 while True:  
@@ -74,10 +74,20 @@ while True:
     #z_x-=8
     road_x-=8
     bg_x-=1
-    if zaw.rect.x<= 0-zaw.rect.width:
-        zaw=Block(stone,cacti,apple)
-    screen.blit(zaw.image, (zaw.rect.x, 500-zaw.rect.height))
-    zaw.rect.x-=8
+    #if zaw.rect.x<= 0-zaw.rect.width:
+    time+=1
+    if time>=60:
+        time=0
+        num=random.randint(0,50)
+        if num>20:
+            zaw=Block(stone,cacti,apple)
+            zaw_list.add(zaw)
+    for i in zaw_list:    
+        i.rect.x-=8
+        screen.blit(i.image, (i.rect.x, 500-i.rect.height))
+        if i.rect.x<=0-i.rect.width:
+            i.kill()
+        
         #z=random.choice([stone,cacti,apple])
         #rect=stone.get_rect()
         #z_x=1000