什么是 “two-year-old”?
“two-year-old” 是一个由数字 + 名词 + 形容词构成的复合形容词,用于描述年龄。它通常用来修饰名词,表示“两岁的……”。
注意:当中间有连字符(hyphen)时,它是一个整体形容词,不能拆开使用。
正确用法示例
- 作定语(放在名词前):
- She has a two-year-old son.
- We adopted a two-year-old dog.
- 作主语补足语(表语)时,不加连字符:
- Her son is two years old.
- The dog is two years old.
常见错误
- ❌ She has a two years old son. (错误:作定语时不能用复数形式)
- ❌ Her son is two-year-old. (错误:作表语时不应使用连字符)
- ✅ 正确对比:
- 定语:a two-year-old child
- 表语:The child is two years old.
扩展规则
这种结构适用于所有“数字 + 年/月/天 + old”的表达:
- a five-month-old baby → The baby is five months old.
- a ten-day-old project → The project is ten days old.
关键原则:作定语时用单数 + 连字符;作表语时用复数 + 无连字符。