课程内容
高中英语《健康的生活 Unit 3 A healthy life(Part 3)》（选修6）
It is no use/good doing sth 做...没有用/不
It is fun doing sth     做...很有趣
Proverbs(谚语）with "it"
①It is never too old to learn.
活到老，学到老。
②It is easier to fall than to rise.
摔倒容易爬起来难。
③It is no use crying over spilt（溢出的）milk.覆水难收
④It never rains but it pours(泼水）.
不雨则已，一雨倾盆。
不鸣则已，一鸣惊人
⑤It is easy to open a shop but hard to keep it always open.
创业容易守业难。
⑥It takes three generations(代）to make a gentleman.
十年树木，百年树人。
Read and analyze the sentences.
It is Friday today. date
It was very cold last Monday.     weather
It is about 8:30 now.   time
It is about 510km from Beijing to Shanghai.   distance
It lies in the south of the city.   place
It is 40℃ ！You got a high fever!   temperature
Conclusion:it可以用作非人称代词，表示日期、天气、时间、距离、地点、温度等。
It is obvious that the water was to blame.
It is true that he will treat me for breakfast tomorrow.
It is certain that our class will do a good job in the final exam.
Is it possible that he will become the chairman of our country?
It is amazing that at my age I still look like a student!
分析：it是形式主语，句子真正的主语时that 引导的主语从句。
牢记以下常用于该句型的形容词
It is clear/obvious/true/possibly/certain/amazing/ridiculous等+that从句
思考：为什么要用it 做形式主语而把真正主语放到后面去？
遵循英语语法的尾重原则，避免句子头重脚轻。
The use of"it"
一、用作人称代词，代表前面提到的人或事物
1)Who's it? (It's )me.
2)Look at the picture.(It)is a picture of our school.
二、用于代替指示代词this和that
-Is this jacket yours?
-Yes,(it)is.
三、用以表示时间、距离、天气、气候、季节、环境等
1)It is half past eight now.  Time
2)It's only half an hour's walk from here to our school. Distance
3)I hope that it will be fine tomorrow.   Weather
4)It had rained much this year.    Weather
5)It's spring now.   Season
6)It's quiet here.  Circumstance
四、it用作形式主语
替代作主语的从句、动词不定式、动名词、而把真正作主语的从句、动词不定式、动名词置于句尾。
1.代作主语的动词不定式
1)It be adj.(for sb.)to do sth.
此处adj. 通常为描述事件的形容词：
easy,difficult,hard,necessary,unnecessary,possible,impossible,likely,unlikely,right,wrong,important,unimportant,legal,illegal,well-mannered,polite,impolite,clear,obvious,certain,suitable,proper,fit,useful,useless,dangerous....
2)It be adj. of sb. to do sth.
此处adj.通常为描述人的形容词：
kind,unkind,nice,rude,cruel,considerate,thoughtful,thoughtless,careful,careless,silly,foolish,stupid,clever,wise,crazy
3)It替代作主语的动名词的常见句型
It's no good/use doing....
It's (well) worth doing...
It's (well) worth one's while doing/to do.....
It's (well) worth while doing/to do
It's no use crying over spilt milk.
2.it作形式主语替代主语从句
①It is adj.+clause
It is clear(obvious,true,possible,certain...)that
该句型中it是形式主语，真正的主语是that引导的主语从句，常译为“清楚（显然，真的...）”，是主语从句最常见的一种结构
It is very clear that he's round and tall like a tree.
②It is v-ed that...=sb./sth is to do
It is said (reported/learned/believed/thought/known/told/hoped...)that...
该句型中的it仍是形式主语，真正主语是that引导的主语从句；该结构常译为“据（据报道，据悉....）”。
It is said that he has come to Beijing.
It is reported that another earth satellite has been put into orbit.
③It is + noun +从句
It is a pity(a shame/an honor/a good thing/a fact/a surprise/...)that...
该句型中，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。如：
五、it作形式宾语
当符合宾语中的宾语是不定式、动名词宾语从句时，往往把宾语放在它的补足语后面，而用it作形式宾语，放在宾语补足语之前。
该句型中的it作形式宾语，常用的动词有think,believe,make,find,consider,feel等。
I think it no use arguing with him.
我认为和他争吵没有用。
I found it very interesting to study English.
我发现学英语非常有趣。
He made it clear that he was notinterested in this sbuject.
他非常清楚地表示他对那门学科不感兴趣。
六、用于强调句型中
It+be +被强调部分+that/who(a person)从句
I met Tom in the park yesterday.
1)It was I who met Tom in the park yesterday.
2)It was Tom who I met in the park yesterday.
3)It was in the park that I met Tom yesterday.
4)It was yesterday that I met Tom in the park.
It was five o'clock when I got home.
It was at five o'clock that I got home.
七、it常用的固定搭配
1.make it
1)在口语当中相当于succeed,表示：成功、做到、说定、赶上、及时赶到 如：
It's hard to make it to the top in show business.
2)在口语中相当于fix the date for,表示“约定好时间”
-Shall we meet next week?
-OK.We just make it next Saturday.
2.take it/things esay
相当于Don't worry or don't hurry,用来劝告别人，表示“不要慌，别担心，沉住气”
Take it easy!He will do it well.
3.It all depends/that all depends在口语中，相当于it hasn't been decided yet,表示“那得看情况，还没有定下来”
Are you going to the countryside for holiday?
-It/That all depends.
4.It's up to sb.
在口语中，相当于it's decided by sb.表示“由...决定，由...负责，取决于...”
-Shall we go out for dinner?
-It's up to you.