词法-It 的用法全解析

📌 1. 代替前面提到的名词

• 用法：It 指代前面提到的单数名词，避免重复。
• 例子：
  • He took a stone and threw it.
    • It = the stone，代替前面提到的石头。

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📌 2. 代替前面提到的短语或从句

• 用法：It 可指代前面提到的短语或整个句子，常用于评价或总结。
• 例子：
  1. He is trying to win a scholarship to Harvard. He won’t find it easy.
     • It = “to win a scholarship to Harvard”，代替整个短语。
  2. He advised me to do so, but I thought it quite useless.
     • It = “to do so”，指代前面的建议。

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📌 3. 表示时间、天气、距离、温度、季节等

• 用法：It 用作无实义主语，描述客观状态。
• 例子：
  • It is fine today. （今天天气很好）
  • What a hard winter it is! （这个冬天真冷！）
  • It is five miles there. （那儿有五英里）

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📌 4. 代替中性名词或动物

• 用法：It 可指性别不明的人（如婴儿）或动物，通常中性。
• 例子：
  • The child lost its way.
    • Its = his or her，指性别不明的孩子。
  • A cow is a useful animal. It gives us milk.
    • It = the cow，指代动物。

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📌 5. 形式主语或形式宾语

• 用法：It 代替真正的主语或宾语（通常是动词不定式或从句），使句子更简洁。

形式主语

• 结构：It’s + 形容词 + to do sth / that 从句
• 例子：
  1. It’s a pity to make a fool of you.
     • 真正主语：To make a fool of you（愚弄你是件遗憾的事）。
  2. It doesn’t matter what you do.
     • 真正主语：What you do（你做什么无所谓）。
  3. It’s important to learn English.
     • 真正主语：To learn English（学英语很重要）。
  4. It was easy getting the equipment loaded.
     • 真正主语：Getting the equipment loaded（装设备很容易）。

形式宾语

• 结构：动词 + it + 形容词 + 真正宾语（to do / that 从句）
• 例子：
  1. I find it exciting working here.
     • 真正宾语：working here（我发现在这儿工作很刺激）。
  2. He made it his business to settle the matter.
     • 真正宾语：to settle the matter（他把解决问题当成了自己的职责）。

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📌 6. 引导强调句

• 用法：It is/was + 强调部分 + that/who/which/when/where，突出句子中的某个成分（主语、宾语、副词等）。
• 结构特点：去掉 It is/was 和 that 后，句子仍完整。

例子与分析

• 原句：English is important in our life.
  • 强调主语：It is English that is important in our life.
    • 强调 English。
• 原句：He fell ill during the voyage.
  1. 强调主语：It was he that fell ill during the voyage.
     • 强调 he。
  2. 强调复数主语：It was they that fell ill during the voyage.
     • 强调 they。
  3. 强调时间：It was during the voyage that he fell ill.
     • 强调 during the voyage。

特殊情况

• 强调人：可用 who 代替 that。
  • It was he who fell ill during the voyage.
• 强调物：可用 which 代替 that。
  • It was the book which I read yesterday.
• 强调时间：可用 when。
  • It was yesterday when he arrived.

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💡 总结：It 的核心用法

1. 代替名词：指代前面单数事物。
2. 代替短语/句子：总结或评价前面内容。
3. 无实义主语：描述时间、天气等。
4. 中性指代：指婴儿或动物。
5. 形式主语/宾语：简化复杂结构。
6. 强调句：突出句子某部分。

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🧠 小练习（试试看！）

1. He bought a car and sold ___ last week.
   • A. it B. this C. that D. these
   • 答案：A
2. ___ is sunny today.
   • A. This B. That C. It D. These
   • 答案：C
3. ___ was Tom who helped me yesterday.
   • A. This B. It C. That D. These
   • 答案：B