from random import randint from time import time, sleep def download_task(filename): print('开始下载%s...' % filename) time_to_download = randint(5, 10) sleep(time_to_download) print('%s下载完成! 耗费了%d秒' % (filename, time_to_download)) def main(): start = time() download_task('Python从入门到住院.pdf') download_task('Peking Hot.avi') end = time() print('总共耗费了%.2f秒.' % (end - start)) if __name__ == '__main__': main()