zhèngshì jiézhǐ shì gěi lǎoshī de, nèibù jiézhǐ shì gěi xiǎozǔ jiǎnchá, hébìng hé jiùhuǒ de

正式截止是给老师的，内部截止是给小组检查、合并和救火的。

The official deadline is for the teacher, while the internal deadline is for the team to review, merge, and handle emergencies.