import pygame
# 初始化pygame，为使用pygame做准备
pygame.init()


screen = pygame.display.set_mode((680,480))
while True:
   for event in pygame. event.get():
      if event.type==locals.QUIT:
           exit()

screen.blit(background,(0, 0))

screen.blit(right,(240, 120))  

screen.blit(food,(360, 300))

pygame.display.update()