四大 + Noun
The phrase 四大 (sì dà) means "four great" or "four major" and is used as a fixed modifier to classify the most important or representative items in a category. It appears in many set phrases such as 四大发明 (four great inventions) and 四大传统节日 (four major traditional festivals). It always precedes the noun it modifies.
造纸术是中国四大发明之一。
Zàozhǐshù shì Zhōngguó sì dà fāmíng zhī yī.
Papermaking is one of China's Four Great Inventions.
春节、清明节、端午节和中秋节是中国的四大传统节日。
Chūn Jié, Qīngmíng Jié, Duānwǔ Jié hé Zhōngqiū Jié shì Zhōngguó de sì dà chuántǒng jiérì.
The Spring Festival, Qingming Festival, Dragon Boat Festival, and Mid-Autumn Festival are China's four major traditional holidays.
他被评为公司四大优秀员工之一。
Tā bèi píng wéi gōngsī sì dà yōuxiù yuángōng zhī yī.
He was named one of the company's four outstanding employees.