Unit 3 A Healthy Life Period 3 Grammar –The Use of “It” (1)
Learning aims: To master the structure and use of “it”
Important point and difficult point: To learn to use “it” correctly and properly.
使用说明及学法指导：1. 自我学习同步测练P 的内容，完成预习案。 2. 完成时间20分钟。
预习案Previewing Case
Task 1课文原句填空并分析所填单词在句中所充当的成分。
1．_________ is a beautiful day here and I am sitting under the big tree at the end of the garden. ( )
2．________ seems amazing that at my age I am still fit enough to cycle 20 kilometers in an afternoon. ( )
3．________is my birthday in two weeks time and I’ll be 82 years old! ( )
4．Your mother tells me that you started smoking some time ago and now you are finding _______ difficult to give ______ up. ( )
5．Believe me，I know how easy __________is to begin smoking and how tough _________is to stop. ( )
6．This means that after a while your body becomes accustomed to having nicotine in_________. ( )
7．As you know，if you do the same thing over and over again，you begin to do _______ automatically. ( )
8．I didn’t know，for example，that __________could do terrible damage to your heart and lungs or that __________was more difficult for smoking couples to become pregnant. ( )
Task 2 分析下列句中it的用法。
1. Tom's mother kept telling him that he should work harder but it didn't help. ( )
2. —Who is knocking at the door? —It's me. ( )
3. It is some 3000 kilometers from Beijing to Guangzhou. ( )
4. It's getting colder and colder every day. ( )
5. They watched the train until it disappeared in the distance. ( )
小结：代词it的用法
用法
例句
代替前文提过的东西或事情，避免重复
Tom joined the army last month. Do you know about it?
This is a new dictionary. I bought it yesterday.
指代前句或后句所述的抽象事物或抽象环境和情景
I hate it when people talk with a full mouth.
代替指示代词，起着this或that的作用
Is this your car? —No, it isn’t.
What’s that? —It’s a video.
指明某人或某物的身份，还可指不明性别的婴儿
Who’s there? —It is John.
The Greens have a new baby. It’s lovely.
指时间，距离，自然现象（天气、气候、明暗），量度，价值等
It is a lovely day, isn’t it? 指天气
It was nearly midnight when she came back. 指时间
It is/ has been 10 years since he lived here. 指时间
It was not long before they arrived. 指时间
It is April First today. 指日期
How far is it to the Great Wall? 指距离
It is three dollars. 指价值
Today it is 30 degrees centigrade. 指温度
我的疑惑：
探究案 Exploring Case it 用作形式主语
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探究一 it替代作主语的不定式
1．It+ be+ adj.+（for sb.）+to do sth. 不定式的逻辑主语是由for引起，主句中的形容词通常是表示重要性，紧迫性，频繁程度，难易，安全等情况的中性形容词。常见的形容词有easy, difficult, hard, necessary, possible, likely, right, wrong, important, legal, polite, clear, obvious, certain, suitable, proper, fit, useful, dangerous等。
例: It is illegal for a teenager to drive a car without a license.
[仿写](1)当今掌握一门外语是很有必要的。______________________________________________________________________________________________
2. It+ be+ adj.+（of sb.）+to do sth. 不定式的逻辑主语是由 of引起，主句中的形容词必须是能表示逻辑主语特征的褒义或贬义形容词。常见的形容词有brave, careless, clever, cruel, foolish, good, honest, kind, lazy, nice, considerate, thoughtful等。
例: It is kind of you to help me with this problem.
[仿写]一再的相信他的话，你真的太愚蠢了。
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3. It takes sb … to do sth. “做…花费某人…”
例: It took thousands of people many years to build the Great Wall.
[仿写]修理电视机花了他一个星期的时间。
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探究二it替代作主语的动名词
It替代作主语的动名词，常见句型有：
(1)It is no good / no use / useless doing sth. 做……是没有用的。
(2)It is worth/ worthwhile doing sth. 做……是值得的。
例: It is no use crying over spilt milk.
[仿写]为了学业放弃游戏是很值得的。
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探究三 it代替做主语的从句
it作形式主语的几种句型：
(1) It is +adj. (clear, obvious, true, possible, certain…) + that从句.
(2) It is +adj. (important, necessary…) + that+sb (should) do sth.
(3) It is + p.p. (said, reported, believed, thought, known, told…) + that 从句.
(4) It is suggested/ advised/ ordered/ demanded/ insisted/ commanded+ that +sb (should) do sth.
(5) It is time ( about time, high time ) that从句(虚拟语气:动词用过去时did)
(6) It is the first ( second ... ) time + that从句(从句用现在完成时 have done )
It was the first ( second ... ) time + that从句(从句用过去完成时had done )
(7) It is a pity ( a shame /an honour/a good thing/a fact/a surprise/... ) that从句。that后的从句一般用虚拟语气（should + 动词原形）, should可省去。表示出乎意料, 常译为“竟然”。没有这种意义时, 则不用虚拟语气。
(8) It happens/ seems/ appears) +that从句.
例: (1)It is important that we (should) learn English well.
(2) It is no secret that the president wants to have a second term at office.
(3)It is a pity that such a thing (should) happen in your class.
[仿写](1)这是我第一次听到这么奇怪的事情。
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(2)是时候为高考做准备了。
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训练案：翻译下列句子。
1. 跟他聊天是浪费时间。_______________________________________________________________________
2. 你认为和他吵值得吗？_______________________________________________________________________
3. 他父亲已经去世三年了。_____________________________________________________________________
4. 很明显地球围绕太阳转 ______________________________________________________________________
5. 按要求我们明天之前要把作业交上去。_________________________________________________________
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