3 sentences

1. 欧阳是中国的复姓之一。

   ōu​yáng shì Zhōng​guó de fù​xìng zhī yī.

   Ouyang is one of China's compound surnames.

   Source: Dong Chinese Dictionary

2. 在下复姓欧阳。

   zài xià fù​xìng ōu​yáng.

   My compound surname is Ouyang.

   Source: Dong Chinese Dictionary

3. 在下复姓欧阳，不知阁下如何称呼？

   zài xià fù​xìng ōu​yáng, bù zhī gé​xià rú​hé chēng​hu?

   My humble name is Ouyang; how may I address you?

   Source: Dong Chinese Dictionary