高中英语语法：it 的用法及与it有关的句型

it 的用法及与it有关的句型 一、It 的用法概括 用作代词 It it 作形式主语 it作形式宾语 用作引导词 It引导的其它句型 It 引导强调句型 二、 It 用法详解 1. it 用作代词 主要用法 举例 1 用作人称代词，代替前文提到的同一事物 --- Where is my book? --- It is in your schoolbag 2[来源:学_科_网] 用于代替指示代词 ---- What’s that? --- It is a piano 3 表示天气，时间，距离，环境等 It is seven o’clock now. It is summer now.[来源:学+科+网] It is about five kilometers from here to the railway Station. 4 用来指一个未亲眼看到，面目不详的人或指婴儿 --- Who is it? --- It is me, Tom. What a lovely baby! Is it a boy? 5 用来代替整个句子或句中谓语部分所表示的意思 You have saved my life. I shall never forget it. 2.it 用作形式主语 当动词不定式，动名词或从句作主语时，通常把它们放在谓语之后，而用it作句子的形式主语。 主要用法 举例 1 It 代替不定式作主语 [来源:学科网ZXXK] It is important to keep fit It is very important for me to study English well. It is very kind of you to help me. It took thousands of people many years to build the Great Wall. 句型：It is +形容词+for sb+to do It is +形容词+of sb +to do 常用描述事物的形容词： easy difficult hard possible necessary