12. Os.system ()--Execute shell commands. Example:On Christmas Eve, Little Charlie and Grandma Lily are decorating the Christmas tree. Little Charlie picked up the last bear doll and handed it to Grandma. The Christmas tree was dressed up. Little Charlie blinked his big eyes, looked at the Christmas tree and then at Grandma, and jumped up happily.准备工作和退路都必须准备好。Moreover, as can be seen from the counter of the second rule in the above figure, no message has been matched by the second rule at all.拍摄期间剧组离奇事件不断，摄影师拍摄到了奇怪的画面，甚至闹出了命案......小葱对红椒道：回头你把这些写在纸上，天天教他背。又是兵？杨寿全一拍脑袋，儿子这辈子是跟当兵的干上了
