3 sentences

1. 纽是希腊字母表中的一个字母。

   niǔ shì Xī​là zì​mǔ​biǎo zhōng de yī gè zì​mǔ.

   Nu is a letter in the Greek alphabet.

   Source: Dong Chinese Dictionary

2. 斐是希腊字母表中的第21个字母。

   fěi shì Xī​là zì​mǔ​biǎo zhōng de dì21 gè zì​mǔ.

   Phi is the 21st letter of the Greek alphabet.

   Source: Dong Chinese Dictionary

3. 老师要求同学们在课上背诵德语字母表。

   lǎo​shī yāo​qiú tóng​xué​men zài kè shàng bèi​sòng Dé​yǔ zì​mǔ​biǎo.

   The teacher asked the students to recite the German alphabet in class.

   Source: Dong Chinese Dictionary