2027届高考英语一轮复习名词性从句—主语从句
主语从句 完整汇总
知识点+习题专练
一、定义：在句子中充当主语的从句，功能等同于名词，属于名词性从句。
二、两种句式结构
1. 从句直接置于句首
从句放主句最前面作主语，结构：主语从句 + 谓语 + 其他
例：That he will attend the meeting is certain.
2. it 作形式主语（最常用）
为避免句子头重脚轻，用 it 暂代主语，真正主语从句后置。
结构：It + 谓语/表语 + 主语从句
例：It is certain that he will attend the meeting.
三、引导词分类及用法
1. that
• 无词义，不充当从句成分，绝对不能省略
• 句首、后置句式均可使用
例：That she likes music is obvious.= It is obvious that she likes music.
2. whether（是否）
• 有词义，不充当从句成分；句首只能用whether，不能用if
例：Whether we go or stay hasn't been decided.
3. 连接代词（what/who/whom/whose/which）
• 有词义，在从句中作主语、宾语、定语
例：What you need is more time.（what 作宾语）
Who will take part is unknown.（who 作主语）
4. 连接副词（when/where/why/how）
• 有词义，在从句中作时间、地点、原因、方式状语
例：How we solve the problem matters a lot.
四、核心语法规则
1. 语序：从句一律使用陈述语序❌ Where does he live is unknown.
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✅ Where he lives is unknown.
2. 主谓一致：单个主语从句作主语，主句谓语动词常用单数
例：What he thinks is right.
3. 时态：遵循主从句时态呼应规则；若从句为客观真理，始终用一般现在时。
五、高频固定句型（it 形式主语）
1. It is + 形容词 + that… It is clear/important/strange that…
2. It is + 名词 + that… It is a fact/a pity/a rule that…
3. It + 不及物动词 + that… It seems/happens/turns out that…
六、重难点辨析：that vs what
• that：从句句子成分完整，只起连接作用，无实义
That he is late makes me angry.（从句主谓完整）
• what：从句缺少主语/宾语，what 补充成分，译为“……的人/事/物”
What he did makes me angry.（did 缺少宾语）
主语从句 专项练习题
一、单项选择（15题）选择合适的引导词填空。
1. ______ he will come to the party is not known yet.
A. If B. Whether C. What D. That
2. ______ makes me happy is my family’s love.
A. That B. What C. Which D. How
3. It is clear ______ he is good at English.
A. what B. whether C. that D. why
4. ______ we will hold the sports meeting depends on the weather.
A. When B. What C. That D. Who
5. It is a pity ______ you missed the wonderful film.
A. how B. that C. if D. whether
6. ______ broke the window has not been found out.
A. Who B. What C. Whom D. Which
7. ______ he solved the problem is a mystery to us all.
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A. What B. How C. That D. Which
8. It seems ______ he has known the truth.
A. that B. what C. when D. where
9. ______ you choose is all right with me.
A. Whatever B. What C. That D. How
10. ______ the earth goes around the sun is a basic fact.
A. What B. Which C. That D. Whether
11. It is unknown ______ he will arrive.
A. what B. when C. that D. how many
12. ______ I need most is more free time.
A. That B. Which C. What D. How
13. ______ he will accept our advice is still a question.
A. If B. Whether C. That D. What
14. It is strange ______ he didn’t answer my call.
A. why B. that C. when D. where
15. ______ we should do next hasn’t been discussed.
A. How B. What C. That D. When
二、句型转换（5题）将句首主语从句改写为 it 作形式主语 的句式。
- That he will win the game is certain.
- Where we can find help is unknown.
- Whether she will join us is still a problem.
4. What he said moved everyone.
- How they finished the work so fast is surprising.
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