初中it, one,that,those的用法
I. it／one ／that三者均可用作代词, 指代前面提到的名词。一般说来, it指代同名同物; one 与that则指代同名异物。
I have lost my umbrella; I'm looking for it. （该句中it就是指前面的my umbrella）
I have lost my umbrella; I think I must buy one. （one在该句中表泛指, 因为my umbrella 已经丢了）
The umbrella you bought is cheaper than that I bought. （替代词that在该句中特指“the umbrella I bought”, 以区别“the umbrella you bought”）
II. one与that虽可用来指代同名异物, 但one为泛指, 相当于a／an＋名词; that为特指, 相当
于the ＋名词。所以one所指代的名词的修饰语一般为 a／an ／some ／any; that所指代的名词的修饰语往往是the ／this ／that。
A chair made of steel is stronger than one made of wood. （该句中one可以换成a chair）
The water in the cup is hotter than that in the pot. （该句中that可以换成 the water）
III. one只能代替可数名词单数, 代替可数名词复数时用ones; that既可以代替不可数名词也可以代替可数名词单数, 代替可数名词复数时用 those。
I like this pen more than that one. （one代替可数名词单数pen）
There were a few young people and some older ones in the house. （ones代替可数名词复数people）
Mary's handwriting is far better than that of Peter. （that代替不可数名词 handwriting）
These pictures are more beautiful than those. （those代替可数名词复数 pictures）
IV. one既可代替事物, 也可代替人, that只能代替事物而不能代替人。有时可以用the one或the ones代替that或those。
The one ／That on the table is mine. （该句中The one代替事物, 并且也可以用That）
He is the teacher, the one who is loved by the students. （该句中the one代替人, 不能用that）
He advised the farmers to choose the best seed-heads, the ones ／those that had the best color. （该句中the ones代替事物, 并且也可以用those）
V. one一般有前置修饰语, 有时也可有后置修饰语或不用修饰语。而 that不能有前置修饰语, 但可有后置修饰语。
Cook was a strict but good captain, one who took good care of his sailors.
The water in the well is cleaner than that in the river.
VI. it可以替代句中的不定式或从句等, 充当形式主语或形式宾语。one与that均无此用法。
It is known to everybody that the moon travels around the earth once every month.
I found it hard to get on with her.
VII. it与that均可以替代上文全句的内容或部分内容, 而one ／ones则不可以。
He has saved my life; I'll never forget it. （it代替第一分句）
Tom is painting his house. I am told he does it every four years. （it代替前面分句的部分内容painting his house）
Let's say we meet here at three o'clock. That ought to give you time to buy everything. （That代替前面表述的内容）
［相关练习］
1. Mr Zhang gave the textbooks to all the pupils except _____ who had already taken them.
A. the ones
B. ones
C. some
D. the others
2. I find _____ easy enough to get on with Pam.
A. that
B. this
C. one
D. it
3. If I can stop her coming to you, I shall do_____.
A. those
B. which
C. these
D. it
4. I haven't a pen. Can you lend me_____?
A. these
B. those
C. them
D. one
5. _____ is necessary that I get the text of my revision typed.
A. There
B. This
C. That
D. It
6. I took _____ for granted that you would stay with us.
A. it
B. that
C. these
D. them
7. Few pleasures can equal _____ of a cool drink on a hot day.
A. some
B. any
C. that
D. those
8. Of all my old friends, the only _____ I saw much of was Betty.
A. it
B. that
C. one
D. this Key: 1—8ADDDDACC
it的用法归纳
?Never be afraid of grammar ?Collect some examples; ?Watch them very carefully; ?Find out something in common; ?Try to use the rules ---- practise. it用法完全归纳 一、it 作人称代词的用法 1.指事物 作为人称代词，it 可以除人以外的一切事物或动物。如： I dropped my watch and it broke. 我把手表掉在地上摔坏了。 It’s hard work, but I enjoy it. 工作很辛苦，可是我乐意干。 “Where is the dog?”“It’s in the bedroom. ”“狗在哪?”“在卧室里”。 2.指人 it 指人主要用于指不性别不明的婴儿或用于确认某人的身份。如： Is it a boy or a girl? 是男孩还是女孩? There is a knock on the door. It must be the postman. 有人在敲门，一定是邮递员。 【说明】在答语中，常用来指本人，如说It’s me。
3.代替某些代词 代词it 还可用于代替指示代词this, that 以及复合不定代词something, anything, nothing等。如： “What’s this?”“It’s a new machine. ”“这是什么?”“是一种新机器”。 Nothing is wrong, is it? 没出什么问题，是吗? 二、it 作非人称代词的用法 1.基本用法 it 作非人称代词的用法，主要用于指时间、距离、价值、天气、气候及温度等自然现象。如： It’s too late to go there now. 现在去那儿已经太迟了。 It rained all day yesterday. 昨天下了一天的雨。 It can get very hot here. 这里有时会很热。 2.用于某些句型 It’s time for sth. 该做某事了。 It’s time to do sth. 该做某事的时候了。 It’s time for sb to do sth. 某人该干某事了。 It’s (about / high) time + that-从句. 某人该做某事了。(从句谓语用过去式，有时也用“should+动词原形”) It’s first (second) time + that-从句. 某人第几次干某事。(从句谓语用现在完成时)
(完整版)初中it用法练习题
---------------------------------------------------------------最新资料推荐------------------------------------------------------ 初中it用法练习题 初中 it 用法练习题在英语中,it 有许多不同的用法,它既可以用作代词，也可以用作引导词，还可以用来构成强调句型。 1. it 用作代词用作人称代词在句子中作主语或宾语；指前面已经提到过的事物、动物或人，且 it 指特定的事物；如果指前文中提到的事物中的任何一个，用 one。 one 可以与 any, each, every, not 等连用，但 one 不可代替不可数名词。 Wheres your car? Its in the garage. 你的汽车在哪儿呢？在车库里。 Did you hit it? 你打中了吗？ The baby cried when it was hungry.这婴儿饿时就哭。 Who is that? Its me. 是谁？我。 Whats this? Its a box. 这是什么？一只箱子。 作非人称代词表示天气、日期、时间、温度、距离、价值、路程、度量、自然现象与环境等。 也可模糊地指一般情形或上文的部分或整个意思。 译成汉语时，it 通常不一定译出来。 Its a long time since they left. 他们走后很久了。 Its two miles to the beach.离海滨有两英里远。 Thats just itI cant work when youre making so much 1/ 24
it用法专项练习题
it用法专练 一．替代词it, that, (the) one(s), those的用法辨析 1. The award on the left is more beautiful than _______ on the right. A the one B one C it D this 2. Few pleasures can equal ________of a cool drink on a hot day. A. some B. any C. that D. those 3. The hunter’s younger sister is taller than the elder ___. A the one B one C that D this 4. I need the plastic bags, not the paper______ . A the one B ones C that D this 5. The TV sets made in China are much better than ________ in Japan. A．that B．those C．them D．It 6. Listen to________! We will have three days off. A the one B ones C that D this 7. “A penny saved is a penny earned.” Who said_________? A the one B ones C that D this 8. I bought a dictionary three years ago and I am still using______ now. A one B ones C it D this 9. I bought a dictionary three years ago but I am going to buy a new _______soon. A one B ones C it D this 10. I was disappointed with the film. I had expected____ to be much better. A.that B. this C. one D .it 11 Equipped with modern facilities, today's libraries differ greatly from______. A. those of the past B. the past C. which of the past D. these past 12.My most famous relative of all, ___who really left his mark on America,wasReb Sussel,my great-grandfather. A. one B. the one C. he D. someone 13. He has one blue pen and two red ________. A. one B. those C. one's D. ones 14. Cars do cause us some health problems —in fact far more serious than_____ mobile phones do. A. one B. ones C. it D. those 15. Cook was a strict but good captain, ______ who took good care of the sailors on his ship. A. that B. one C. it D. what 16. Mr Zhang gave the text books to all the pupils except____who had already taken them. A.these B.ones C.the ones D.the others 17. —— I'm looking for a flat. —— Would you like ____ with ____ garden? A．it; the B．it; a C．one; a D．one; the 18.Meeting my uncle after all these years was an unforgettable moment, ___I will always treasure. A.that B.one C.it D.what 19. The style of the building is similar to _________of a temple. A.that B.one C.it D.what 20. The computers in our school are connected to the Internet while___in their school aren’t. A.that B.one C.it D.those 21.Our food and service are better than ________ used to be. A．it B．that C．they D．those 22.I’m moving to the countryside because the air there is much fresher than _____ in the city. A. ones B. one C. that D. those 23.We’ve been looking at houses but haven’t found _____we like yet.
高中英语语法知识之It的用法总结
高考英语语法知识之It 的用法总结 1．It is + 被强调部分+ that ... 该句型是强调句型。将被强调的部分放在前面，其它部分置于that之后。被强调部分可以是主语，宾语，状语。强调的主语如果是人，that可以由who换用。 如果把这种句型结构划掉后，应该是一个完整无缺的句子。这也是判断强调句型与其它从句的方法。 It was they that (who) cleaned the classroom yesterday. It was in the street that I met her father. 2．It was not until + 被强调部分+ that ... 该句型也是强调句型。主要用于强凋时间状语，译成汉语＂直到．．．才．．．＂，可以说是not ... until ... 的强调形式。 It was not until she took off her dark glasses that I realized she was a famous film star. = Not until she took off her dark glasses did I realize she was a famous film star. = I didn’t realize she was a famous film star until she took off her dark glasses. 3．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，肯定．．．）＂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.= That he’s round and tall like a tree is very clear. 4. It is important ( necessary, right, strange, natural...) that ... 由于主句中的形容词不同，that 后的从句中要用虚拟语气（should + 动词原形），should 可以省去。 It is important that we (should) learn English well. It is necessary that he (should) remember these words. 5. It is said (reported, learned....) 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＂据说（据报道，据悉．．．）＂。It is said that he has come to Beijing. 6. It is suggested ( ordered ... ) that ... 主句中的过去分词是表示请求，建议，命令等词时，that后的从句要用虚拟语气（should + 动词原形），should 可以省。常译为＂据建议；有命令．． It is suggested that the meeting ( should ) be put off. It was ordered that we ( should ) arrive there in two hours. 7. It is a pity ( a shame ... ) 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。 It is a pity that such a thing ( should ) happen in your class. It is a pity that he is ill. 8. It is time ( about time ,high time ) that ... 该句型中that 后的从句应该用虚拟语气，值得注意的是①常用过去时态表示虚拟．②有时也用should + 动词原形，should 不能省。常译为＂是（正是）．．．的时侯．．．＂。 It is time that children should go to bed. = It is time that children went to bed. 9. It is the first ( second ... ) time that ... 该句型中的that 从句不用虚拟语气，而用完成时态。至于用什么完成时态，由主句的谓语动词的时态决定。如果是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用过去完成时态。该结构中that 可以省去；it有时用this / that 替换．常译为＂这是某人第几次做某事了＂。 It is the first time I have been here. = This is the first time I have been here. 10 It is the +形容词最高级+ 名词+ that + ….. 该句型中的that 从句不用虚拟语气，而用完成时态。至于用什么完成时态，由主句的谓语动词的时态决定。如果是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用过去完成时态。该结构中that 可以省去；it有时用this / that 替换．常译为＂这是某人做过的最…的事情＂。 This is the best film that I have ever seen . That was the worst song that he had heard . 11. It is .... since ...
(完整版)it的用法练习题
it的用法练习题（一） 1.It took us over an hour _____________along the street. A. walk B. to walk C. walking D. walked 2.I think it a great honor ________to visit your country. A. to invite B. inviting C. having invited D. to be invited 3.Many people now make_____________ a rule to buy cards for their friends before Christmas. A. themselves B. it C. that D. this 4._____is very clear to everyone that he's round and tall like a tree. A. This B. What C. That D. It 5.In the United States, bus travel doesn't cost much as train travel,_____________? A. don't they B. does it C. do they D. doesn't it 6.Someone is at the door, who is_____________? A. this B. that C .it D. he 7.—It is raining cats and dogs. —_____________ . A. So it is B. So is it C. Neither it is D. Neither is it 8.—My home is in that tall building over there. —_______________? A. Can it see B. Can see it C. Can be seen it D. Can it be seen 9. _____________raining hard for 3 hours without stopping. A. It is B. It was C. It has been D. It had been 10.—Has the boy got his bicycle now? —Yes, the police gave_____________. A. him to him B. it to it C. it to him D. him to it 11.—Boy, —It is, looks like spring is coming soon.
语法专题十：it的用法
语法专题十：it的用法 1.指代事物、动物、婴儿或未知的人。 2.指天气、时间、距离、自然现象、环境等。 3.代替不定式，作形式主语或形式宾语(常与feel, consider, find, believe, make, take, imagine, think, suppose, regard等连用)。 4.代替动名词，作形式主语或形式宾语： It is no good / no use / useless / dangerous + doing I think it no good / no use / useless / dangerous + doing I think it no use complaining about their prejudice. 5.代替主语从句、宾语从句，作形式主语或形式宾语： It seems / appears / happens / turns out / proves + that… It is certain / likely / possible / probable + that… We have made it clear that she has nothing to do with the case. 6.用于强调句：It is / was … that / who… A student witnessed the car accident at the turning last night. (1 ) ( 2 ) ( 3 ) ( 4 ) (1) _________________________________________________________. (2) _________________________________________________________. (3) _________________________________________________________. (4) _________________________________________________________. It is not until +被强调的部分+ that… I didn’t realize she was a famous film star until she took off her dark glasses. ________________________________________________________________. 7. 其他重要句型： It is important (necessary, right, strange, natural) that…（should+动词原形） It is said (reported, learned…) that… It is suggested (ordered…) that…（should）+动词原形 It is a pity (a sham) that …（should）+动词原形 It happens (seems, looks, appears ) that... It occurs to sb. to do / that…：使某人想起…… It is/ has been +一段时间+ since ...+过去时 It will be +一段时间+ before ... It looks ( seems ) as if … It is no wonder…：难怪 When it comes to…：当谈到…… It comes about that…：发生 8. appreciate, love, like, hate, see to(负责，注意) + it + 从句 巩固练习： 1. It took us over an hour ______ along the street. A. walk B. to walk C. walking D. walked 2. I think it a great honour ______to visit your country. A. to invite B. inviting C. having invited D. to be invited 3. Many people now make ______a rule to buy cards for their friends before Christmas. A. themselves B. it C. that D. this 4.______is very clear to everyone that he's round and tall like a tree.
It的用法专题训练20题
It的用法专题训练20题 It的用法专题训练20题 湖南省涟源市私立行知中学曾省初 【典型例题】1. (NMET2001单项填空) The Parkers bought anew house but _____will need a lot of work before they can move in. A. they B. it C. one D. which 【思路点拨】B此题考查it 指代前面的a new house. 2.{MET93单项填空} Tom’mother kept telling him that he should work harder , but ____ didn’t help. A. he B. which C. she D. it 【思路点拨】D此题考查it 指代前面一句话，因有but,故which不能引导非限制性定语从句。 3.(NMET98，单项填空) It was only when I reread his poems recently ____I began to appreciate their beauty． A．until B．that C．then D．so
【思路点拨】B 此题考查强调句，所以用that 4.(MET 2000上海单项填空) It was how the young man had learned five foreign languages______ attracted the audience’s interest. A. so that B. that C. what D. in which 【思路点拨】B 此题考查强调句，所以用that 1. Was it during the Second World War_____ he died? A .that B .while C. in which D .then (88) 2. Is ____ necessary to complete the design before National Day? A. this B .that C. it D .he (89) 3. I don't think ____ possible to master a foreign language without much memory work. A .this B. that C .its D .it (91) 4 .Does ______ matter if he can't finish the job on time? A. this B .that C .he D it (91) 5 .It was not _____ she took off her glasses _____ I realized she was a famous film star. A .when , that B .until , that C .until , then D. when , then (92) 6.I was disappointed with the film . I had expected ______ to be much better. A. that B. this C. one D .it (93)
高中语法it的用法
it的用法 一、考点聚焦 1、it的基本用法 （1）用作人称代词，代替前文提到过的事物。 The train has arrived. It arrived half an hour ago. （2）用以代替提示代词this, that。[来源:学,科,网Z,X,X,K] —What’s this? —It’s a knife. —Whose watch is t hat? —It’s mine. （3）起指示代词的作用，指一个人或事物。 —Who is knocking at the door? —It’s me. （4）指环境情况等。 It was very noisy(quiet) at the very moment. （5）指时间、季节等。 —What time is it? —It’s eight o’clock. It often rains in summer here. （6）指距离。 It is a long way to the school. （7）作形式主语。 It is not easy to finish the work in two days. It is no use crying over spilt milk. It is as pity that you didn’t read the book. （8）作形式宾语。 I think it no use arguing w ith him. I found it very interesting to study English. He made it clear that he was not interested in that subject. （9）用于强调结构。 It was Xiaoming whom(that)I met in the street last night. It was in the street that I met Xiaoming last n ight. It ws last night that I met Xiaoming in the street. It was I who met Xiaoming in the street last night. 2、含有“It is …”的句型 （1）It is time (for sb.) to do sth. It is (high) time that sb. did sth.(虚拟语气) （2）It is + 形容词（+of / for sb.）+ to do sth 通常用 of的词有brave、clever、careful、hopeless、kind、good、naughty、nice、silly、stupid、foolish、wise 等。 （3）It is + 形容词+ that + sb. + (should) do sth.（虚拟语气）[来源:学科网ZXXK] 能用于这个句型的形容词有strange、wonderful、natural、good、proper、right、wrong、well、fortunate、important、necessary、useless、likely、probab le、impossible等。有时可省去should而直接用动词原形。如：It is important that we should pay close attention to grain. It is natural that he（should）say so. （4）It is no use/ good + doing sth. It is no use trying again = It is of no use to try again. （5）It is + 被强调部分+ that/who + …[来源:学科网ZXXK][来源:Z+xx+https://www.360docs.net/doc/317231211.html,] Was it in the street that you met her? Who was it that called him“comrade”? It was not until yesterday that I met my old friend.
高中英语It的用法专项练习题
高中英语It的用法专项练习题一 1. Was it during the Second World War_____ he died? A.that B.while C.in which D.then 2. Is ____ necessary to complete the design before National Day? A.this B.that C.it D.he 3. I don't think ____ possible to master a foreign language without much memory work. A.this B.that C.its D.it 4. Does ______ matter if he can't finish the job on time? A.this B.that C.he D.it 5. It was not _____ she took off her glasses _____ I realized she was a famous film star. A.when, that B.until, that C.until, that D.when, then 6. I was disappointed with the film. I had expected ______ to be much better. A.that B.this C.one D.it 7. It was not until 1920 ______ regular radio broadcasts began. A.while B.which C.that D.since 8. ______is a fact that English is being accepted as an international language. A.There B.This C.That D.It 9. It was only when I reread this poems recently _____ I began to appreciate their beauty. A.until B.that C.then D.so
初中英语语法：it用作人称代词的用法
初中英语语法：it用作人称代词的用法 it用作人称代词的用法 1. 用于指事物 it用作人称代词最基本的用法就是代替前面已提到过的事物，以 避免重复： This is my watch, it’s a Swiss one. 这是我的手表，它是瑞 士制的。 I cannot find my watch; I must have lost it. 我找不到手表，我一定把它给丢了。 2. 用于指动物或婴儿 除用于指代事物外，还可指动物或性别不详的婴儿： “Where is the cat?” “It’s under the bed.” “ 猫在哪儿?”“在床下。” They got a baby and it was very lovely. 他们生了个孩子， 很可爱。 3. 用于上文提到的情况 He smokes in bed and I don’t like it. 他在床上抽烟，我不 喜欢他这样。 Her mother kept telling her not to go out at night, but it didn’t hel p. 她母亲老叫她晚上不要出去，但是没用。 4. 用于指人 it用于指人主要用确定未知人的身份： “Who is it?” “It’s me.” “是谁啊?”“是我。”
“Listen. Someone is crying.” “Oh, it must be Mary.” “听，有人在哭。”“噢，一定是玛丽。” Someone must have been here. But we have no idea who it was. 一定有人来过，但我们不知道是谁。 5. 指人时与he和she的区别 当it用于指人时，主要用于确定未知的或者是身份不明的人，若 是指已知的或身份明确的人，则应根据情况使用he或she。比较： I hear a knock at the door. It must be the postman. 我听 见有人在敲门，一定是邮递员来了。 Jim is at the door. He wants to see you. 吉姆在门口，他想 见你。 A tall man stood up and shook hands with her. It was the general manager. 一个高个子站起来同她握了手，他是总经理。 The general manager just called. He told us to wait for him at the gate. 总经理刚来过电话，他叫我们在门口等他。 6. 指物时与one的区别 两者均可代替前面提到的事物，区别是：it指的是与前面已提到 的事物为同一物，此时的it等于“the (this, that, my...)+名词”;而one 指的是与前面已提到的事物为同一类物，此时的one等于“a+ 名词”。比较： I have a dictionary but I’ve lent it to Mary. 我有一本词典，但把它借给玛丽了。 I haven’t a dictionary; can you lend me one? 我没有词典，你能借我一本吗?
it的用法训练题
综合训练十：It的用法 It的用法在高考中也是重现率较高的语言点，尤其是it用于强调句。其考查方式多通过“语法填空”进行，偶尔也出现在“完形填空”中。 一、要点点拔 1．代替上文中提到过的人或事物。指代人时，一般用于小孩或身份不十分明朗的人。 1) －Who is the baby? －It…s my teacher?s son． 2) －Who is that gentleman? －It's my friend Tom．He(不可用It) wants to see you． 2．用于表达天气、环境、时间、距离、季节等。例如： 1) It?s half an hour?s walk from here to our school． 2) It…s nice and warm here． 3) But it's two o'clock now, and it's time for us to go to school． 3．用作形式主语.it 没有具体意义，而只是帮助把真正的主语移至句子后尾，使句子显得平稳一些，能借it 给移至句子后尾的主语有三种：一种由不定式表示，一种由动名词表示，一种由从句表示。 1).It 替代真正的主语——动词不定式短语. It is easier to say than to do . It is a good act to help the others. 2).it 替代真正的主语——动名词短语,以动名词短语做主语的句子，主要在以no good, no use, no harm, dangerous, foolish 等词作表语的句中. It?s no harm drinking running water in that area。 It?s foolish talking like that. 3).it 替代从句作主语，用从句做主语的带it 的句子很多,常见的有下面几类： ①It is a pity (a shame ,a fact ,a wonder ,a good thing,etc. )that… It is a shame that he didn?t pass the exam. ②It is strange ( surprising,obvious ,true, good,possible,clear,etc. ) that… 。 It was clear that they had no desire for peace. ③It seems (happened ,turned out,etc.)that… It seemed that things were not as they expected. ④It is said ( decided ,expected ,etc)that … It is said that the tickets have been sold out . 4.用作形式宾语。 当复合宾语中的宾语是不定式,－ing短语或从句往往用it作形式宾语,而将真正的宾语移至句末,句子重心后移。 1) We find it difficult to learn English well in such a short time． 2) We think it no use crying over spilt milk． 3) We made it clear when and where we were going to have the meeting． 5．用于强调句型，即“It is/was＋被强调部分＋that/who/whom+其它”句型之中。 使用该句型有以下几点请注意： ①强调句的谓语is或was永远用单数. It was yesterday that I met your father in the street． ②不管被强调部分是哪种状语，只能用that连接，不得使用where、when等连词. It was in the street that I met your father yesterday．
第二章 “It”用法及其句型和固定搭配讲解
第二章“It”用法及其句型和固定搭配讲解 "It" 用法及其句型和固定搭配，是高中英语语法的重点、难点，又是近几年高考的热点，因此应给予充分的重视，现将it用法归纳如下： 一、It用作实词 表达以下概念:指代前文提到的事物，前文中的this, that;替代前文中的内容;指代一位性别不明的小孩或未知的人;指代未指明但谈话双方都知道的那件事;指代时间、天气、气候、距离等自然现象…… 二、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。 It 作形式主语的常见句型： 1. 代作主语的动词不定式，其句型为 (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, ill-mannered, polite, impolite, clear, obvious, certain, suitable, proper, fit, useful, useless, dangerous… 例 It is illegal (for a teenager) to drive a car without a license. (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. 例 It's kind of you to help me with the problem. (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… I t's (well)worth one's while doing/to do… It's (well)worth while doing/ to do