"First" 可以是不同词性，主要有副词、形容词和名词。
1. **副词 (Adverb):**
- 例句: She finished her homework first.
2. **形容词 (Adjective):**
- 例句: This is the first time I've visited this city.
3. **名词 (Noun):**
- 例句: He was the first to arrive at the party.
总的来说，"first" 根据上下文可以用作副词、形容词或名词，其使用方式会根据其在句子中的角色而有所不同。
