精确修饰“物”，构建规范句型，提升语法表达水平
一、基本概念：which 在定语从句中的核心作用
关系代词 which 用于引导修饰事物的定语从句，可在从句中作主语或宾语。
示例解析：
- 主语位置：The phone which broke down was expensive.
- 宾语位置：The report which she submitted was well-organized.
which 所引导的定语从句位于先行词之后，用于进一步说明或限定先行词的内容。
二、限制性与非限制性定语从句对比
限制性定语从句（无逗号，提供必要信息）：
The book which you recommended is excellent.
非限制性定语从句（用逗号隔开，补充说明）：
This dictionary, which I bought last week, is very helpful.
⛔ 注意：非限制性定语从句只能使用 which，不能使用 that。
三、与关系代词 that 的使用对比
| 项目 | that | which |
|---|---|---|
| 修饰对象 | 人 / 物 | 物 |
| 可用于限制性从句 | ✅ | ✅ |
| 可用于非限制性从句 | ❌ | ✅ |
| 正式写作中推荐使用 | 一般 | ✅ 更常用 |
✅ 举例说明：
- 正确：I admire the plan which was proposed by the team.
- 正确：The device, which was tested yesterday, passed all safety checks.
四、句式转换训练
请将以下句子合并为包含定语从句的复合句：
- She designed a logo. The logo represents our brand.
→ She designed a logo which represents our brand. - He read an article. It discussed climate change.
→ He read an article which discussed climate change.
五、范文片段解析（学术/考试写作场景）
The research, which was conducted over a period of six months, yielded unexpected results.
The model which the team developed significantly improved prediction accuracy.
上述例句展示了 which 在专业写作中清晰表达附加信息与限定条件的优势。
六、常见误区提醒
- ❌ My car, that is red, is fast.（非限制性从句不能用 that）
- ✅ My car, which is red, is fast.
- ❌ I like books which talks about history.（主谓不一致）
- ✅ I like books which talk about history.
七、知识点小结
- which 用于修饰物；
- 可在从句中作主语或宾语；
- 非限制性从句中只能使用 which；
- 正式书写建议使用 which 表达更规范。
掌握 which 引导的定语从句，不仅可以让你的表达更加准确，还能在书面写作中体现更高的语法水平。为了帮助你巩固理解并灵活运用该结构，我们推荐使用「李校来了英语AI训练系统」，系统将通过结构识别、语法纠错与句型重构训练模块，帮助你实现从掌握知识到熟练表达的跨越。