英语 it的用法 学习笔记

一、it 的基本用法概述

it 是第三人称单数、中性的人称代词，既可以指代事物，也可指代时间、天气、距离、情景、想法等抽象内容。

常见功能

1. 指代上文提到的事物

2. 表示时间、天气、距离等

3. 作形式主语 / 形式宾语

4. 用于强调结构

5. 用于固定句型

二、it 的具体用法详解

1️⃣ 指代事物或动物（无生命或未知性别）

• This is my book. It is interesting.

  （这是我的书，它很有趣。）

• I have a cat. It is black.

  （我有一只猫，它是黑色的。）

  婴儿性别不明时也可用 it：

• The baby is crying. It looks hungry.

✅ 特点：避免重复名词，使语言简洁。

2️⃣ 表示时间、天气、距离、环境

✅ 特点：it 在句中没有具体指代对象，是形式主语。

3️⃣ it 作形式主语（真正主语在后面）

当主语是不定式、动名词或从句时，常用 it 放在句首作形式主语，把真正的主语放在句末，使句子平衡。

常见结构

• It + be + 形容词 + to do / doing / that 从句

示例

• It is important to learn English.

  （真正主语是 to learn English）

• It is no use crying over spilt milk.

  （真正主语是 crying over spilt milk）

• It is clear that he was wrong.

  （真正主语是 that 从句）

✅ 特点：避免头重脚轻，增强可读性。

4️�️⃣ it 作形式宾语（真正宾语在后面）

当宾语是不定式、动名词或从句，且宾语补足语较长时，常用 it 作形式宾语。

常见结构

• 主语 + 动词 + it + 宾语补足语 + 真正宾语

示例

• I find it difficult to understand him.

  （真正宾语是 to understand him）

• He made it clear that he would not come.

  （真正宾语是 that 从句）

• We think it important to protect the environment.

✅ 特点：使句子结构更自然、平衡。

5️⃣ 强调句型：It is … that / who …

用于强调句子中的某个成分（主语、宾语、状语等）。

基本结构

It is / was + 被强调部分 + that / who + 其他部分

示例

• I met Tom in the park yesterday.

• 强调主语：It was Tom that I met in the park yesterday.

• 强调地点：It was in the park that I met Tom yesterday.

• 强调时间：It was yesterday that I met Tom in the park.

✅ 注意：

• 强调人时可用 who，其他情况多用 that

• 去掉 It is … that 结构，句子仍然完整

6️⃣ 用于固定句型

• It seems / looks / appears that …

  It seems that he is ill.

• It looks as if …

  It looks as if it is going to rain.

• It happens that …

  It happened that I saw him yesterday.

• It depends.

  — Will you come? — It depends.

三、易错点提醒

❌ 错误：避免用 it 指代“人”（除非是婴儿或性别不明）

• He is my brother. He is tall. (不说 It is tall)

❌ 错误：强调句型中 that / who 不可省略

• It was Tom that I saw. (正确)

• It was Tom I saw. (口语可接受，但正式写作不建议省略)

四、总结