关系从句
Relative clauses modify a noun phrase by adding identifying or supplementary information and must attach unambiguously to their antecedent.
01 · 概念基础
先理解术语，再应用规则
以下术语指向不同的语法对象，应比较其功能与例句，而非只记翻译。
relative clause/ˈrelətɪv klɔːz/
mệnh đề quan hệA clause modifying a noun phrase and usually introduced by who, which, that, whose, where or when.
the station that recorded the peak
trạm đã ghi nhận giá trị đỉnh
defining relative clause/dɪˈfaɪnɪŋ ˈrelətɪv klɔːz/
mệnh đề quan hệ xác địnhA relative clause necessary to identify the intended referent and written without surrounding commas.
The stations that failed were replaced.
Những trạm bị hỏng đã được thay.
non-defining relative clause/nɒn dɪˈfaɪnɪŋ ˈrelətɪv klɔːz/
mệnh đề quan hệ không xác địnhA supplementary relative clause separated by commas and not required to identify the referent.
Station A, which failed, was replaced.
Trạm A, vốn bị hỏng, đã được thay.
完整课程范围
不要停留在单一公式
限制性与非限制性关系从句
who、whom、whose、which、that、where 与 when
主语/宾语关系从句与关系词省略
介词位置、句子性 which 与缩减关系从句
判断边界：关系从句应紧邻先行词；只有补充信息才使用逗号。
02 · 控制规则
关系从句把一个命题附着于名词短语。限定性从句缩小指称范围，通常不用逗号；非限定性从句补充信息，并用逗号或停顿隔开。关系词在从句内部承担语法功能。作主语的关系词不能省略，作宾语时有时可省；缩减关系从句用 V-ing 表示主动、V3 表示被动，或用不定式表示目的、顺序或潜在性。
head noun + who/whom/whose/which/that/where/when + clause | head + V-ing/V3/to-infinitive reduced relative关系从句：限定、补充与受控缩减
把信息附加到正确名词，区分限定与非限定关系从句，准确选择或省略关系标记，并仅在指代清楚时缩减。
关系从句属于名词短语。首要任务是限定或描述名词；随后标点与关系词指示信息是否必要、补充，以及关系词作主语还是宾语。
限定从句缩小指代范围，非限定从句添加插入信息。作主语的关系词不能省略，作宾语时有时可省略，that 不能用于非限定从句。缩减为 V-ing、V3 或不定式是保义转换，而非机械删除。
先行词是哪一个名词，从句是否直接附着于它？
删除从句会改变所指的人或物吗？
关系词作主语、宾语、所有格、地点、时间还是原因？
从句能否在不改变语态、时间关系或主语控制的情况下缩减？
1. 限定与非限定信息
限定从句说明所指类别成员；非限定从句假定指代已明确，并用逗号与口语停顿添加额外信息。
defining: noun + relative clause · non-defining: identifiable noun, relative clause,限定从句不用分隔逗号，因为信息与名词识别融为一体。
非限定从句书面需逗号，口语需语调边界。
that 可在许多限定从句中替代 who/which，但不能用于非限定从句。
The sensors that recorded continuous data were retained.
记录连续数据的传感器被保留。
限定从句选择传感器子集。
The ADCP, which was installed in May, failed during the storm.
该 ADCP 于五月安装，在风暴期间失效。
设备已明确，从句仅添加背景信息。
限定关系从句
noun + who/which/that/whose/where/when + clause限制指代并识别所指成员。
the method that produced the lowest error
the researcher whose paper we cited
- 不用分隔逗号；作宾语的关系词有时可省略。
非限定关系从句
identifiable noun, who/which/whose/where/when + clause,添加插入信息而不改变指代。
The Thames, which flows through London, ...
- 使用逗号且不用 that。
缩减关系从句
noun + V-ing/V3/to-infinitive压缩可恢复的主动、被动或识别关系。
students studying abroad
data collected in 2025
the first method to converge
- 缩减前检查语态与隐含主语。
逗号改变指代
The students who submitted early received feedback.
只有提前提交的学生收到反馈。
The students, who submitted early, received feedback.
所有已明确学生都提前提交；从句是补充信息。
标点编码从句是否限制指代集合。
主语关系与宾语关系
The model that failed was replaced.
that 是 failed 的主语，不能省略。
The model (that) we tested was replaced.
that 是 tested 的宾语，在限定从句中可省略。
决定省略前，先看关系词后是否已有明确主语。
介词前置与留置
the method on which the analysis relies
正式书面语。
the method the analysis relies on
中性且常见于口语。
按语域选择；附着清楚时两者均可。
雅思口语
- 优先
- 用简短 who/which 从句识别人、地点与经历，非限定信息自然停顿。
- 避免
- 避免大量 whom 或深层嵌套影响流利度。
- 原因
- 关系从句应扩展回答而不增加过多处理负担。
雅思写作任务二
- 优先
- 限定从句用于分类，非限定从句用于简洁背景。
- 避免
- 避免逗号错误导致无意声称所有成员具有同一属性。
- 原因
- 指代精度影响论证准确性。
科学定义与报告
- 优先
- 从句紧邻先行词，仅在语态与主语可恢复时缩减。
- 避免
- 避免远距离附着导致修饰错误名词。
- 原因
- 错置关系从句可能改变科学命题。
不要机械翻译标记：应重建关系与视角
关系标记
关系代词/副词与标点明确标记语法角色和从句类型。
越南语常把描述分句置于名词后，而无明显 who/which/that 对应词。
译入英语时，先识别缺失语法角色，再选择或省略关系词。
限定区别
逗号与语调可改变从句是否限制指代。
类似区别可能更依赖语境与停顿，标点提示不那么强制。
不要机械复制越南语标点；应判断英语从句是必要还是插入。
按功能选择关系词
that 限于限定从句；whom 主要正式且作宾语。
| 功能 | 关系词 | 可省略？ |
|---|---|---|
| 人-主语 | who/that | 否 |
| 人-宾语 | whom/who/that | 限定中可 |
| 物-主/宾语 | which/that | 仅宾语 |
| 所有 | whose | 否 |
| 地点/时间 | where/when | 可改写 |
关系从句缩减图
缩减是可选的，必须保留目标关系。
| 完整从句 | 缩减形式 | 意义 |
|---|---|---|
| people who live nearby | people living nearby | 主动 |
| data that were collected | data collected | 被动 |
| the first method that achieved convergence | the first method to achieve convergence | 顺序/识别 |
✕ The ADCP, that was installed in May, failed.
✓ The ADCP, which was installed in May, failed.
that 不用于非限定关系从句。
✕ The sensor recorded the peak was replaced.
✓ The sensor that recorded the peak was replaced.
作主语的关系词不能省略。
✕ The researcher who she designed the survey presented the results.
✓ The researcher who designed the survey presented the results.
who 已是 designed 的主语。
✕ Students, who need support, should contact the tutor.
✓ Students who need support should contact the tutor.
若无语境表明所有学生都需帮助，应使用限定从句。
依据关系、视角与语篇功能选择
1. 哪句表示只保留部分传感器？
2. 哪个关系词可省略？
3. 哪种缩减形式是被动？
4. 哪种形式适合非限定从句？
写一个自然使用非限定关系从句的雅思口语回答、一个用限定关系从句的科学定义，以及一个方法句中的缩减关系从句，并解释各自先行词与语法功能。
从句直接附着于目标名词。
逗号选择符合限定或非限定意义。
关系词主/宾语角色正确。
任何缩减均保留语态与指代。
03 · 解析示例
同时观察形式、功能与意义
The stations that recorded complete series were retained.
Các trạm ghi được chuỗi đầy đủ đã được giữ lại.
The estuary, which receives strong tidal forcing, requires a finer grid.
Cửa sông, nơi chịu tác động thủy triều mạnh, cần lưới mịn hơn.
The researcher whose dataset was used is listed as a co-author.
Nhà nghiên cứu có bộ dữ liệu được sử dụng được liệt kê là đồng tác giả.
The method on which the analysis relies is documented in Appendix A.
Phương pháp mà phân tích dựa vào được trình bày trong Phụ lục A.
Sensors installed below mean sea level require corrosion protection.
Các cảm biến được lắp dưới mực nước biển trung bình cần được bảo vệ chống ăn mòn.
The first team to complete the survey will validate the metadata.
Nhóm đầu tiên hoàn thành khảo sát sẽ kiểm định siêu dữ liệu.
04 · 高风险错误对比
说明错误原因，而非只选正确答案
The sensor which it failed was replaced.
The sensor which failed was replaced.
which 已经是 failed 的主语，再加 it 会形成双主语。若关系词作宾语，则需要另一个主语，而且关系词有时可以省略。
05 · 掌握检测
完成课程前先应用规则
哪个句子符合目标语法系统？
哪个描述最能定义“relative clause”？
哪个例句属于本课已验证的目标结构？
哪个结构公式属于本课？
完成四项检测，然后提交自拟句以获得目标结构反馈。
06 · IELTS Academic
将语法迁移到真实交际任务
在口语中，关系从句可在不另起一句的情况下加入识别或描述信息；非限定性从句需要自然停顿。在写作中可用于定义、分类和压缩证据，但应避免过度嵌套的名词短语。逗号会改变意义，因此标点属于语法的一部分。
能通过指称、逗号和语调区分限定与非限定意义。
能按语法角色使用 who、whom、whose、which、that、where、when。
仅在语法和语域允许时省略宾语关系词。
能把完整关系从句准确缩减为 V-ing、V3 或不定式结构。