4 sentences

1. 她是同类中的第一个。

   tā shì tóng​lèi zhōng de dì​yī​gè.

   She's the first of her kind.

   Source: OpenSubtitles

2. 阿尔法是第一个希腊字母。

   ā'ěr​fǎ shì dì​yī​gè Xī​là zì​mǔ.

   Alpha is the first letter of the Greek alphabet.

   Source: Dong Chinese Dictionary

3. 我想成为第一个知道所有事情的人。

   wǒ xiǎng chéng​wéi dì​yī​gè zhī​dào suǒ​yǒu shì​qing de rén.

   I want to be the first to know everything.

   Source: OpenSubtitles

4. 夏启是中国历史上第一个王朝的开创者。

   Xià Qǐ shì Zhōng​guó lì​shǐ​shàng dì​yī​gè wáng​cháo de kāi​chuàng zhě.

   Xia Qi was the founder of the first dynasty in Chinese history.

   Source: Dong Chinese Dictionary