三更燈火五更雞

Etymology

From the Tang poem “An Exhortation to Learning” (勸學):

三更燈火五更雞，正是男兒讀書時。黑髮不知勤學早，白首方悔讀書遲。 [MSC, trad.][▼ expand/hide]
三更灯火五更鸡，正是男儿读书时。黑发不知勤学早，白首方悔读书迟。 [MSC, simp.]

From: Tang Dynasty, Yan Zhenqing, “An Exhortation to Learning” (勸學)

Sāngēng dēnghuǒ wǔgēng jī, zhèngshì nán'ér dúshū shí. Hēifà bùzhī qín xué zǎo, báishǒu fāng huǐ dúshū chí. [Pinyin]

Third watch (~ 11 p.m.) with lamp light and fifth watch (~ 5 a.m.) as the rooster crows,
Are the best time for a boy to study.
If one does not study hard while his hairs are still dark,
he will regret for studying late when his hairs turn grey.

Pronunciation

Idiom

三更燈火五更雞

1. to burn the midnight oil, only to get up at the crack of dawn
2. to work long hours
3. to burn one's candle at both ends
   • 就是這樣的一道檻，讓眾多的學子“三更燈火五更雞”，讓眾多的學校加課補課取消節假日。 [MSC, trad.]
     就是这样的一道槛，让众多的学子“三更灯火五更鸡”，让众多的学校加课补课取消节假日。 [MSC, simp.]

     From: 2004: 武少民 (Wu Shaomin), 来信选登:素质教育比不上高考升学率？ (Letters to the Editor: Quality education cannot compare to the rate at which students pass high school entrance exams?)

     Jiùshì zhèyàng de yī dào kǎn, ràng zhòngduō de xuézǐ “sāngēng dēnghuǒ wǔgēng jī”, ràng zhòngduō de xuéxiào jiākè bǔkè qǔxiāo jiéjiàrì. [Pinyin]

     It's just this kind of threshold that causes many students to study late into the night, only to get up and go to class the next morning. It also causes many schools to add extra classes, including make-up classes, and to cancel holidays and days off.