Introduction
第 (dì) turns a number into an ordinal. 一 (yī) is "one"; 第一 (dì yī) is "first". The prefix never changes shape, and everything else about the number phrase stays exactly as it was — measure word included.
Overview
Structure: 第 (dì) + Number + (Measure Word + Noun)
| Pattern | Example | Translation |
|---|---|---|
| 第 + Number | 第一 (dì yī) | first |
| 第 + Number + MW + N | 第一个人 (dì yī ge rén) | the first person |
| 第 + Number + MW | 第二本 (dì èr běn) | the second one |
| 第一次 | 第一次来中国 (dì yī cì lái Zhōngguó) | first time in China |
| 第几 | 你是第几个？(Nǐ shì dì jǐ ge?) | Which number are you? |
第 (dì) does not replace the measure word:
- ✓ 第一个人 (dì yī ge rén) — the first person ❌ 第一人 (dì yī rén)
- "Two" stays 二 (èr) in an ordinal, never 两 (liǎng): ✓ 第二个 (dì èr ge) ❌ 第两个 (dì liǎng ge).
- 一 (yī) keeps its first tone after 第: 第一 is dì yī, not dì yí.
- 第几 (dì jǐ) asks for the position, and like 几 (jǐ) it takes a measure word: 你住第几层？(Nǐ zhù dì jǐ céng?)
Examples
我是第一个到的。
Wǒ shì dì yī ge dào de.
I was the first to arrive.
这是我第一次来中国。
Zhè shì wǒ dì yī cì lái Zhōngguó.
This is my first time in China.
请看第二课。
Qǐng kàn dì èr kè.
Please look at Lesson Two.
他是我的第一个中文老师。
Tā shì wǒ de dì yī ge Zhōngwén lǎoshī.
He was my first Chinese teacher.
你住第几层？
Nǐ zhù dì jǐ céng?
Which floor do you live on?
第三个星期我习惯了。
Dì sān ge xīngqī wǒ xíguàn le.
By the third week I had got used to it.
Usage Notes
- 第 (dì) attaches only to a number, never straight onto a noun: 第一 (dì yī)、第二 (dì èr)、第十 (dì shí).
- Dates and months take no 第 (dì). The 一 in 一月 (yīyuè) — January — is already ordinal on its own, and 十月三号 (shíyuè sān hào) needs nothing added.
- 第一次 (dì yī cì) — the first time — is the most useful phrase in this lesson: 我第一次吃中国菜。(Wǒ dì yī cì chī Zhōngguó cài.)
- Floors, lessons and rounds all take 第 (dì): 第五层 (dì wǔ céng)、第二课 (dì èr kè).
- 第一 (dì yī) also means "the best" or "number one": 他是我们班第一。(Tā shì wǒmen bān dì yī.)