一、为什么需要强调句
同一个事实，英语可以用不同的语序去突出不同的信息重点。当我们想把句子中的某一成分（主语、宾语、状语）推到聚光灯下时，最常用的手段就是强调句型：
It is / was + 被强调部分 + that / who + 句子其余部分
原句：Tom broke the window yesterday.（汤姆昨天打破了窗户。）
| 强调对象 | 强调句 |
|---|---|
| 主语 Tom | It was Tom who/that broke the window yesterday. |
| 宾语 the window | It was the window that Tom broke yesterday. |
| 时间状语 yesterday | It was yesterday that Tom broke the window. |
| 地点状语（假设 in the classroom） | It was in the classroom that Tom broke the window. |
同一个句子可以变出四种强调句，这正是高考语法填空和改错最爱考的角度。
二、三个测试，判断它到底是不是强调句
很多同学失分，不是因为不会造句，而是因为把强调句和别的 It 句型搞混了。以下三个测试可以现场验证。
测试一：去掉 It is … that，句子是否仍然完整？
把 It was … that 三个词抽掉，剩下的词按原顺序能否组成一个完整的句子？
- It was in 2010 that he came to Guiyang. → 抽掉后：He came to Guiyang in 2010. ✅ 完整，是强调句。
- It is important that we should protect the environment. → 抽掉后：We should protect the environment important. ❌ 不通，这是 It 作形式主语的主语从句。
这个测试是最好用的一招，务必练到条件反射。
测试二：that 在从句中充当成分吗？
强调句里的 that 只是一个结构词，不充当任何句子成分，也不能换成 which（指物时 which 在部分语法体系中可接受，但考试以 that 为准）、where、when。
- It was in the park that we met. （that 不作成分，不能说 where）
- This is the park where we met. （where 作地点状语，是定语从句）
测试三：谓语动词能强调吗？
不能。强调句型只能强调主语、宾语、状语等名词性成分，不能强调谓语。要强调谓语，用助动词 do / does / did：
- I do believe you.（我确实相信你。）
- He did come yesterday.（他昨天确实来了。）
- Do be careful!（务必小心！）
三、not until 的强调句：必考结构
原句：He didn't go to bed until his father came back.
强调 until 状语时，要把 not 一起提前，构成固定结构：
It was not until his father came back that he went to bed.
三个要点：
- not 必须跟着 until 一起被强调，不能写成 It was until … that he didn't go to bed.
- that 后面的句子要用肯定形式（he went to bed），因为 not 已经提前了。
- 该结构常与倒装句互转：Not until his father came back did he go to bed.
| 句型 | 例句 |
|---|---|
| 正常句 | He didn't go to bed until his father came back. |
| 强调句 | It was not until his father came back that he went to bed. |
| 倒装句 | Not until his father came back did he go to bed. |
三种表达意思完全相同，只是信息重心不同。写作时交替使用，可以显著提升句子多样性。
四、特殊疑问句的强调形式
把特殊疑问词放进强调结构，形成「疑问词 + is/was + it + that …」：
- Who was it that broke the window?
- When was it that you saw him?
- Where is it that they will hold the meeting?
- How is it that you didn't notice the mistake?（你怎么会没注意到这个错误？）
注意语序：疑问词在最前，it 在中间，不能写成 Who it was that broke the window?（除非作宾语从句：I don't know who it was that broke the window.）
五、It 的四种易混句型对照
| 句型 | 结构特征 | 例句 | 判断方法 |
|---|---|---|---|
| 强调句 | It is/was + 被强调成分 + that/who + 其余 | It was in 2010 that he came. | 去掉 It is…that 仍完整 |
| 形式主语 | It is + adj./n. + that 从句 / to do | It is important that we protect nature. | 抽出后句子不成立；that 从句有完整主谓 |
| 形式宾语 | 主语 + 谓语 + it + adj. + to do/that 从句 | I find it hard to finish the task. | it 代替后面的不定式或从句 |
| 定语从句 | It is/was + 名词 + that/who 引导的从句 | It is the book that I bought yesterday. | 抽出后 The book I bought yesterday 不完整 |
特别提醒：第五行最容易误判。It is the book that I bought yesterday 抽出后剩下 The book I bought yesterday，这是个名词短语而非句子，说明 that 引导的是定语从句，修饰 the book，整个句子并不是强调句。区分的关键在于「抽掉之后剩下的是句子还是短语」。
六、真题式例题解析
例1（语法填空） It was not until midnight ______ he finished his homework.
解析：填 that。这是 not until 的强调句型，只能用 that，不能用 when。
例2（单句改错） It was in the library where I found the missing key.
解析：where → that。去掉 It was … 后 In the library I found the missing key 完整，说明是强调句，强调地点状语时仍用 that。
例3（句型转换） He didn't realize his mistake until his teacher pointed it out.（改为强调句）
答案：It was not until his teacher pointed it out that he realized his mistake.
注意：主句由否定变肯定，时态保持一致。
例4（选择） — ______ that he managed to pass the exam? — By working day and night.
A. How was it B. How it was C. It was how D. Was it how
解析：选 A。特殊疑问句的强调形式语序为「疑问词 + was + it + that」。
例5（写作升级） 原句：The teacher's encouragement changed my attitude. 升级：It was the teacher's encouragement that changed my attitude.
在续写或应用文中，用一句强调句点出关键转折，能让文章的重点更清晰。但一篇作文最多用一到两次，用多了反而显得刻意。
七、当堂练习
练1 用强调句分别强调划线部分（每句写两个不同强调对象的版本）：
- Mary met her old friend at the train station last Sunday.
- The volunteers cleaned up the river bank.
练2 填空：
- It was in 2008 ______ the Beijing Olympic Games were held.
- It is the ability to keep learning ______ matters most.
- It was not until he lost his health ______ he realized its value.
练3 改错（每句一处）：
- It was in the park where we took these photos.
- It was not until 10 p.m. when he came back.
- It is I who is responsible for the mistake.
点击查看答案
**练1**： 1. It was **at the train station** that Mary met her old friend last Sunday. / It was **last Sunday** that Mary met her old friend at the train station. 2. It was **the volunteers** who/that cleaned up the river bank. **练2**：1. that 2. that 3. that **练3**： 1. where → that（强调句） 2. when → that（not until 强调句只能用 that） 3. is → am（强调句中的 who 从句谓语与被强调主语保持一致；正式文体也可保留 is，但中学考试按 am 判分）八、课后作业
基础题（必做） 1. 用 It is/was … that 结构各造两个强调句，分别强调主语和状语。 2. 默写 not until 结构的三个版本（正常句、强调句、倒装句），并注明共同点。
提高题（选做） 3. 从你近期读过的英文文章里找出三个强调句，分析各自强调了什么成分，起了什么表达作用。 4. 把下面这段话改写得更有重点（至少用一次强调句）： 「Our class won the competition. Everyone worked hard. Our teacher helped us a lot.」
挑战题（拓展） 5. 辨析下面两句在结构上的差别，并说明判断依据： a. It was the day when we first met. b. It was on that day that we first met. 6. 写一段 80 词左右的短文，描述一次让你改变想法的经历，要求使用一个强调句和一个 not until 强调句，并在文后标出这两句。
学习提示：强调句的所有考点，最后都归结到一个动作——去掉 It is/was 和 that，看剩下的部分是否还是完整句子。把这个测试练熟，语法填空、改错、句型转换三类题的正确率会一起上去。