Warming up
1．What kind of entertainment did they have?
entertainment作为名词，有以下含义:
1.表示“娱乐，游艺，技术表演”。
e.g.Jenny is interested in the news of entertainment.詹妮对娱乐新闻感兴趣。
2.表示“招待，款待”。
e.g.1.This hotel is famous for its entertainment.这家旅馆因为殷勤待客而出名。
e.g.2.He gives numerous entertainments to his friends.他常常宴请很多客人。
entertainment的动词形式是entertain，它作为及物动词，表示以下含义：
1.使娱乐，助兴e.g.We were all entertained by his tricks.大家对他的把戏都很感兴趣。
2.款待，招待e.g.He plans to entertain his friends to dinner.他计划设晚宴招待他的朋友们。
3.心存，考虑 e.g.1.to entertain an idea/to entertain a hope 怀有一个主意/怀有一个希望
e.g.2.I refused to entertain such a foolish idea.我拒绝考虑这样愚蠢的主意。
entertain作为不及物动词，表示的意思是“招待客人”。
e.g.She loves to talk,dance and entertain.她喜欢说话，跳舞和招待客人。
entertainer作名词，含义是“招待人，款待人；表演娱乐的人”。
entertaining 是形容词，意思是“娱乐的，有趣的”。
e.g.We spent an entertaining evening at the theatre.我们在这家剧院度过了一个有趣的夜晚。
entertainingly 是副词。
2. decoration [U] 装饰，装潢 home decoration 家居装饰
decorate v. 装饰；点缀。例如：decorate a Christmas tree 装饰圣诞树
3. artefact [C] 人工制品（尤指有考古价值的工具或武器）
prehistoric artefacts made of bone and pottery 史前的骨制及陶制器具
4. unearth vt.（从地下）发掘；揭露。
例如：unearth buried treasure 发掘埋在地下的宝藏
unearth new facts about Shakespeare 发现有关莎士比亚的新资料 unearth a plot 揭露一个阴谋
unearth 由un-加上名词 earth构成，类似的词语主要有以下几个。
unhand 意思是“放手，松手”。e.g.Please unhand me!别拉着我。
unglove 的含义是“脱下的手套”。 e.g.Her hand,when ungloved,glitters with heavy rings.
她脱下手套的时候，许多戒指在她手上闪烁。
unhair 的意思是“拔掉头发”。unmask 的意思是“揭除面具或者伪装”。
unglue 的意思是“取掉（粘着之物），剥”。
e.g.1.to unglue a stamp from an envelope by steaming 借着蒸气来取掉信封上的邮票
e.g.2.to unglue the children from a TV set使孩子们离开电视机
Listening
5. else adv. 此外，另外（与不定代词、疑问代词或否定副词连用）。例如：
Do you want anything else? Where else can I get it?
构成所有格时，’s加在else之后。例如： Who else’s fault could it be then?
Speaking
6.I’d like to know more about life as it was two hundred years ago.
as conj. 像……一样的；如……的。例如： I’d like to go abroad as you do.我想跟你一样出国。
as用作“虽然，尽管”时，引导让步状语从句，需提前名词、形容词、副词或动词。例如：
Object as you may, I’ll go. 纵使你反对，我也要去
He was late, as usual. 他如往常一样迟到了。
7.be curious to… 极想……
be curious about… 对……有兴趣
curious adj. 奇异的，奇怪的，好奇心强烈的，渴望知道的，爱探究的。例如：
curious eyes 好奇的眼神 curious behaviour 奇怪的举止
I’m curious to know what is written in his letter. 我极想知道他在信中写什么。
Children are naturally curious about everything around them. 小孩子对周围的每件事感到好奇。
curiosity n. 好奇（心）；古玩；珍品。例如：
arouse curiosity 引起好奇心 a curiosity shop 古董店
8. What I’d really like to find out is whether people would sometimes want to go on a holiday, as we do. That sort of thing 我真正想发现的是人们是否有时候会和我们一样想去度假那一类事情。
as在这里是连词，引导一个方式状语从句。 请看以下由as 引导的方式状语从句的例子：
e.g.1.You’d better do as I did.你最好按照我做的去做。
e.g.2.As what she said before,it was really difficult to persuade him to go with us.
正如她过去所说的，说服他和我们一块走是一件很困难的事情。
作为连词，as还可以引导时间状语从句。
e.g.1.Twelve days later,millions more Indians lined the railway tracks as a slow train took the jar containing his ashes 584 kilometers to a place by the river.
十二天后，当一列慢车将盛有甘地骨灰的坛子驶向584千米外，靠近恒河的一个地方时，又有数百万人排列在铁路两旁，夹道送行。
e.g.2.Three million people watched as the ashes of this great man were gently poured into the brown waters of the river that would carry them to the ocean.
还有300万人守望着这位伟人的骨灰缓缓撒入褐色的恒河，河水把他的骨灰送向大海。
辨析:as,when 和while
这三个连词都可以连接时间状语从句，但有差别:如果主句和从句的时间相同，以选用as较宜，表示随着……；而when只有一般时间意义，还可以表示at that time的含义；while是个连词，它所表达的时间通常是指整个一段时间或过程，相当于during which time的用法。从句中常常使用进行时，还可以表示主从句的对比。
e.g.1.They came up stair as we went down.他们上楼，我们下楼。
e.g.2.As one grows older，one becomes more experienced.人长大了，经验就更丰富了。
e.g.3.When one man is in difficulty，the thousands come to his aid.
一人有难众人帮。
e.g.4.The weather was fine while we were in Shanghai.我们在上海的日子里，天气晴朗。
e.g.5.We were watching TV while they were playing chess.我们在看电视，而他们在下棋。
作为连词，as还可以引导比较状语从句,表示以下含义。
1.表示“（用于比较）与……一样”的意思。
e.g.1.She works in the same building as my sister.她和我的妹妹在同一栋大楼上班。
e.g.2.This is the same as it was before.这个与以前一样。
2.表示“诸如”的意思。
e.g.such animals as cats and dogs 诸如猫、狗之类的动物
作为连词，as还可以引导原因状语从句。
e.g.As the weather is fine,let’s go fishing.既然天气变得好起来了，咱们去钓鱼吧。
辨析:because,since,as 和for
because，since，as引导原因状语从句:
because 引导的从句表示直接的、根本的原因，用来回答why 提出的问题，为全句重心所在。since引导的从句表示显然的或已知的理由、原因，相当于汉语的“既然”。主句是全句意思的重心，从句次之。as 引导原因状语从句，与since没多大区别。它们引导的原因状语从句，其原因已很明显，不必加以强调。由as表示的原因，语气最弱，往往译成汉语的“由于”。
for 是个并列连词，引导并列句，是对前句内容的补充说明。
as还可以用作关系代词，其含义是“正如”请看以下例子。
e.g.As you know，we have the right to vote.正如你知道的，我们有权选举。
辨析:as和which
首先，这两个词意义不同。前者表示正如，后者没有意义，只起连接作用。
其次，前者构成的从句既可以前置又可以后置，而由后者构成的从句则只能后置，不能前置。
再次，当从句中有the same,such,so 时，只能用as。
比较:It is no use arguing with them,as we all see.和他们争论是没有用的，正如我们所看到的。（既可后置）
As we all see，it is no use arguing with them.（又可前置）正如我们都看到的,和他们争论是没有用的。
It is no use arguing with them,which we all see.
我们都看到了，和他们争论是没有用的。（只能后置）
as还可以用作介词，其含义是“作为”。指处于某种状态、性质、情况、工作等之中。请看以下例子。
e.g.1.He works as a driver.他以开汽车为业。e.g.2.The kitten uses that box as a bed.小猫把那盒子当作床。
辨析:as和like
当作介词的时候，as只用于以下情况：
1.用作“作为”讲的时候。
2.用来举例，比如用来代替for example的时候；
3.用来引导某些动词，如:look upon，regard，consider，treat，think of等的宾语的补语的时候。
e.g.1.As a writer，he has no equal.作为一个作家，他是首屈一指的。
e.g.2.Languages（such）as English，German，Dutch belong to the same family.
像英语、德语、荷兰语等语言都属于同一个语系。
e.g.3.The teacher considered your son as being too small.
老师认为你的儿子太小了。
比较:The prisoner was hanged like a murderer.这个囚徒像杀人犯那样被处以绞刑（=…as if he were a murderer）。
e.g.4.The prisoner was hanged as a murderer.这个犯人作为杀人犯被处以绞刑。（这个犯人就是杀人犯）
1.I didn’t feel just you. A.as B.like C.such D.so
2. a teacher,I have to set a good example for my students.
A.Like B.Be C.As D.Have
3.It must have rained yesterday the ground is wet.
A.as B.since C.because D.for答案：1.A 2.C 3.D
Reading
9. date back to: = date from 始自某时期, 追溯到，上溯到(无被动语态)
Our school dates back to 1953. Our friendship dates from childhood.
out of date过时的;旧式的 up to date时新的;新式的
10. bury vt. 埋葬
Many men were buried underground when there was an accident at the mine.
矿上发生意外事故时,许多矿工都被埋在地下
bury oneself in 专心致志于, 埋头于(in)
be buried in thought 沉思 He buried himself in his work.
Buried in his book, he didn’t notice me entering the room.
11.Some of the objects found in the grave give us an idea of how he was dressed when he was buried
墓穴里发现的部分物品让我们对于他当时的穿着有了一个了解
(1)give sb an idea of 使某人明白
The book will give you an idea of what everyday life of ordinary Americans is like.
(2).dress作为及物动词，后面只能够接人或者是反身代词，而不能接物或者是衣服作为宾语。
dress v. 穿衣。例如：
be dressed in （表状态）穿着 dress sb. 给某人穿衣服
dress oneself in… 穿着……（表动作） dress up 盛装，打扮
dress well 穿着得体
dress [C] 连衣裙；女装 in formal (evening) dress 着礼服（晚礼服）
a silk dress 一件丝绸的礼服
12. clothing n.衣服(集合名词,无复数形式) an article of clothing 不能讲a suit of clothing
clothes n.（复）衣服,服装指具体的衣服;无单数形式,不与数词连用但可和many ,a few等表示
不确定的数词连用many clothes, a piece of clothes ,a suit of clothes一件衣服不能讲an article of clothes
Cloth做衣服用的材料,不可数名词, 当作为台布抹布时是可数名词.
13. find [C] 发现，发现物。例如：
Our new gardener was a marvellous find. 我们新找到了一个很出色的花匠。
finding [C] & [U] 发现，发现物
14. dozen n. 一打,十二个 (与数词或many, several等连用时,复数不加s )
two (many, several) dozen pencils 两(好多,几)打铅笔
dozens of 几十,许多 for dozens of years 好几十年以来
pack in dozens 成打地包装 sell by the dozen 论打出售
15. spare adj. 备用的；额外的；多余的；剩下的。例如：
a spare room 预备的房间 a spare tire 备用轮胎 In one’s spare time 在某人闲暇的时候
I have little spare time. 我没有什么余暇。
spare vt. 匀出，分出，省下 例如：Can you spare me just a few minutes? 你能腾出几分钟时间给我吗？
There’s no time to spare. 没有多余的时间了 spare no efforts 不遗余力
Spare the rod and spoil the child. [谚]孩子不打不成器，娇养忤逆儿。（省了棍子坏了孩子。）
16. a variety of / varieties of形形色色的，种种的。例如：
a collection of a variety of butterflies 收集各式各样的蝴蝶
There are a wide variety of people on the earth. 地球上有各种不同的人。
17.The biggest stones weigh 20 tons and came from a place not very far
最大的石头重约20吨，它们来自于一个不远的地方
weigh作为动词，主要表达以下几种含义：
1.表示“称（重量）”。
e.g.1.Let me weigh it.It’s quite a bit overweight.让我来称称它。超重还不少呢。
e.g.2.The goods were carefully weighed at the time of shipment.货物在装运的时候都是仔细称过的。
2.表示“某物有（多少）重量”。
e.g.1.A giant panda can weigh as much as 150 kilos when fully grown.
一只大熊猫长大了，重量可以达到150千克。
e.g.2.Some of the fish already weigh ten kilograms.这些鱼有的已经有10千克重了。
3.表示“压（在上面）”的含义。
e.g.1.The matter weighed heavily on my mind.这件事情沉重地压在我的心上。
e.g.2.The decision has been weighing on my mind all the week.这项决定整整一个星期都压在我的心上。
4.意思是“考虑”。
e.g.1.All the difficulties and risks had to be carefully weighed.所有的困难和风险都要仔细考虑。
e.g.2.They weighed the matter seriously.他们认真考虑了这件事情。
18. link vt., vi.（常与together, to, with连用）连接, 联合
(1)The two towns are linked by a railway.
(2) The new bridge will link the island to the mainland. 新的桥梁将把该岛与大陆连接在一起。
be linked to / have links with 与…有联系
Sichuan have trade links with the Yangtze River. 四川和长江流域有商贸联系。
19.It is possible that the King of Stonehenge was linked to the stones: he may have had a hand in planning the monument,or in helping transport and pull up the stones
巨石阵之王很有可能和石头有联系：他可能参与过巨石阵的设计，或者帮助过巨石的运输
在英语中，may,might,can,could和must几个情态动词都可以用来表示对事情的猜测。must的意思是“肯定，一定”，语气很有把握。may,might,和could的意思是“可能，也许”，语气把握性不大。can的意思是“肯定，也许”，常常用在否定句和疑问句中。这几个情态动词用于表示猜测的时候，其后面可以跟三种不同的动词形式。
1.跟动词原形表示对现在事情的猜测。2.跟表示对现在正在发生的事情的猜测。
3.跟表示对已经发生的事情的猜测。
e.g.1.You are Jack’s best friend.You must know where he is.你是杰克最好的朋友，你一定知道他在哪儿。
e.g.2.Can you hear the loud voice?They must be quarrelling.你能听到那声音吗？他们在吵架。
e.g.3.If you had come earlier,you might have been told the good news.你早来一会儿，就会听到那条好消息了。e.g.4.There is no light in the room.They might have gone out for a walk.屋里没开灯，他们可能出去散步啦。
1.Jack yet,otherwise he would have telephoned me.
A.mustn’t have arrived B.shouldn’t have arrived C.can’t have arrived D.need not have arrived
2.-I stayed at a hotel while in New York.
-Oh,did you?You with Barbara.
A.could have stayed B.could stay C.would stay D.must have stayed
3.-There were already five people in the car,but they managed to take me as well.
-It a comfortable journey.
A.can’t be B.shouldn’t be C.mustn’t be D.couldn’t have been答案:1.C 2.A 3.D
20. have a hand in 参与，插手；对某事负部分责任。例如：
I bet he had a hand in it. 我敢说他一定参与了此事。
I can’t promise much. I’m not the only one that has a hand in this town.
我不能答应太多。镇里的事不是我一个人说了算。
关于hand 的词组还有：
lend a hand 帮助
give sb. A hand 给予帮助
at hand 在手边
by hand 用手
in hand 手头上的，在进行中
hand in hand 手拉手，联合
from hand to hand 从一人之手转到之手
hand down/on 把…传下来
hand in 交上
hand out 把…拿出来，分派
hand over 移交
join hands 携手联合
on one hand,…on the other hand
一方面 ， 另一方面
21. in terms of 用……的话；以……的观点；就……而说。
例如：He thought of everything in terms of money. 他每件事都从钱的角度考虑。
bring a person to terms 使某人接受条件（就范）
come to terms=make terms 达成协议；和好
in the long term 就长期而言
on no terms 无论如何不，决不
on good terms with sb 和某人关系融洽
22. At first it was thought that it was through war and armed conflict,but it is now believed to have happened through trade and cultural links
点拨：1.through指从内部通过。
e.g.1.The thief came in through the window.小偷从窗户进来。
e.g.2.The troops marched through the town.军队从城中走过。
e.g.3.Fish swim through the water.鱼游于水中。
e.g.4.The men cut a tunnel through the mountain.那些人穿山凿了一条隧道。
2.表示“遍及，经历”的意思。
e.g.1.He traveled through Europe.他游遍欧洲。
e.g.2.Other birds and animals stay with you,but you will not see all the animals all through the winter.
另一些飞禽和动物留下来了，但是整个冬天你不会看到所有的这些动物。
3.表示“由于，因为”的含义。
e.g.1.It was all through your being late that we lost the train.我们没有赶上火车，完全是因为你来晚了。
e.g.2.It happened,through no fault of mine.这件事情之所以发生，并非是我的过错。
4.表示“藉，由”的含义。
e.g.1.He became rich through hard work.凭着努力的工作，他致富了。
e.g.2.I obtained my position through a friend.我靠一位朋友的帮忙而得到了这份工作。
5.表示“从头到尾”
e.g.1.He worked from dawn through the day and into the night.他从天亮一直工作到晚上。
e.g.2.He read through the novel carefully.他细心地读完了这本小说。
e.g.3.The rain lasted through the night.雨下了一夜。
比较：through和across的用法
through和across都作“穿过”讲，across指的是从一个空间内的一端到另一端或者是成十字交叉而过。through着重指从物体的中间或者是空间穿过。
e.g.1.Last week,we started our trip across this country.上个星期，我们开始了横跨这个国家的旅行。
e.g.2.We can’t travel through the forest by road,because there aren’t any roads.
我们不能从陆路穿越森林，因为那里根本无路可走。
1.The boy is so good at swimming that he can swim the sea.
2.He walked the forest and disappeared into the valley.答案：1.across 2.through
23. in the eyes of sb. (=in sb.’s eyes): in the opinion of sb.在某人的心目中，在某人看来
In your father’s eyes you’re still a child.
相关词组：keep an eye on sb. 留神，看守，看管
shut (close) one’s eyes to sth. 闭目不看…，装着没看到…，视而不见
Post-reading
1.base…on… 把……基础放在……上；以……为基础。例如：
You should base your conclusion on careful research.你应该以审慎的研究为基础。
This story is based on facts.这故事是有事实根据的。basic adj. 基础的，基本的；根本的
basis [C] 基础；根据
Language study
1.thanks to 多亏，幸亏。例如：
Thanks to modern technology, to find out more facts about the man buried in the grave is possible.
由于现代科技，找出更多的有关埋在墓地里人的材料成为可能
表示原因的结构还有： because of as a result of owing to due to
Integrating skills
2.roots of Chinese culture 中国文化的根源
root [C] 根源，来源；根，根茎。例如：the root of the problem 问题的根源
The love of money is the root of all evil. 爱钱乃万恶之源。（语出《圣经》）
a plant with very long roots 根部很长的植物
Many Americans have roots in Europe. 许多美国人祖籍在欧洲。
get at/to the root of 追根究底
take/strike root 生根，扎根；定居
root and branch adv. 连根地，完全地，彻底地
3. serve as “担当；充当”
4.dig up 挖出；掘起。例如：
We dug up the tree by its roots. 我们将树连根挖起。
An old Greek statue was dug up here last month.
上个月在这儿挖出了一尊古希腊雕像。
dig at 讥讽，挖苦 dig for 挖寻 dig into 详细调查，探求
5.cover作为动词，有很多含义。
1.表示“覆盖，铺盖”。
e.g.1.He covered himself with a blanket.他给自己盖上一床毯子。
e.g.2.A rather cold north west airstream will cover our province.一股偏冷的西北气流将覆盖我省。
e.g.3.When he returned,his body was covered with bruises.他回来的时候全身都是伤痕。
2.表示“走完（一段路程），看完（若干页书），够付（费用）”。
e.g.1.They covered the distance to the place at a run.他们一路小跑，赶到了那个地方。
e.g.2.Here is ten dollars;the extra will cover the bus fares.这儿是10元钱，多余的可以用作坐公共汽车费用。
3.表示“涉及，谈到”的意思。
e.g.1.What are the chief points you are to cover in your talk?你的报告主要有哪些内容？
e.g.2.The discussion covered a wide range of subjects.这项决定涉及到很多别的问题。
4.意思是“有（多少面积），包括（多大的范围）”。
e.g.1.The city covers ten square miles.这座城市的面积是10平方英里。
e.g.2.His burnt area covered 70 per cent of his body surface.他全身的烧伤面积达到了70%。
5.表示“掩护”。
e.g.He ordered us to cover the other people’s withdrawal.他下令让我们掩护其他人撤退。
6.表示“采访，报道”。
e.g.They sent a large number of reporters to cover the conference.他们派遣了大量的记者去报道大会的消息。
Our new school almost 54 square miles,making it the largest school in the province.
A.lies B.stands C.has D.covers答案:D
Grammar
复习代词“it”的用法
It的用法主要有以下一些:
1.作无人称动词的主语，表示时间、气候、距离、状态等。
e.g.1.It’s ten o’clock.现在十点钟了。
e.g.2.It is twenty miles to London.到伦敦有二十英里。
e.g.3.She couldn’t stand it.她真是无法忍受。
2.指代前面出现的事物或者是现象。
e.g.1.Where is my book?Have you seen it？我的书在哪儿?你看见我的书了吗?
e.g.2.He pretended to study,for he thought it would please his mother.
他假装读书,因为他认为那样做可以取悦他的母亲。
3.在特殊情况下指代人。
e.g.1.She got a baby and it was ten-pound.她生了个十磅重的婴儿.
e.g.2.A tall man stood up and shook hands with her.It was the general manager.
一个高个子男子站了起来同她握手,他就是总经理。
4.可以用作形式主语。
e.g.1.It is certain that we shall succeed.我们一定会成功的。
e.g.2.It is necessary for older people to understand what the young think and feel.
年长的人有必要了解年轻人在想些什么,他们有什么感觉。
5.用作形式宾语。
e.g.1.You’ll find it difficult to learn Japanese.你将发现日语很难学。
e.g.2.I make it a rule to take a walk in the morning.我规定自己每天早上散步。
6.用于强调句型。
e.g.1.It is I who am fortunate.幸运的是我。
e.g.2.It was three weeks later that he learnt the news.三个星期以后他得知了这个消息。
◇It is+被强调部分+that…
该句型是强调句型。例如：
It was about 600 years ago that the first clock with a face and an hour hand was made.
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.
◇ 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。例如：
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.
It is important that we (should) learn English well
It is necessary that he (should) remember these words.
◇ 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……）”。例如：
It is said that he has come to Beijing.
It is reported that another earth satellite has been put into orbit.
It is suggested that the meeting (should) be put off.
◇ It is time (about time, high time) that…
该句型中that后的从句应该用虚拟语气。例如：
It is time that children should go to bed. =It is time that children went to bed.
◇ It is the first (second…) time that…
主句如果是一般现在时，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。
该句型中的that从句用完成时态。该结构中that可以省去；it有时用this替换。常译为“是第一（二、三……）次……”。例如：
It is the first time I have been here. =This is the first time I have been here.
It is…since…
该句型主要用作处理瞬间动词的完成时和表示一段时间的时间状语连用的问题。例如：
It is (has been) 5 years since his father died.
It is 5 years since he joined the army.自从他参军5年了。
▲ It is 5 years since he was in the army.自从他退伍已经5年了。
◇It be…before…
该句型主句中的it指时间，主句中的时态常是一般将来时或过去时两种时态。例如：
It was 3 days before he went to Beijing.
It will be not long before he finishes his job.
◇It happens (seems, looks, appears) that…
该句型中it是形式主语，that引导的是主语从句，主句中的happen, seem等词是不及物动词。例如：
It happened (so happened) that he met his teacher in the street.
It seems that he will be back in a few days.
◇It is no good (use) doing sth.
主句中的表语可以是no good, (not any good), no use (not any use)。例如：
It is no good learning English without speaking English.
◇It doesn’t matter whether (if)…
该句型中whether (if) 引导的从句是真正主语，该句型常译为“不论（是否）……没关系……”。例如：
It doesn’t matter if they are old.
◇ It is kind (of sb.) to do sth.
常见的这类形容词有：bad, brave, careless, clever, cruel, foolish, good, honest, kind, lazy, nice, polite, rude, wise, wrong等。
该句型中的不定式短语是真正主语，如果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形容词。这个句型可以改写为：sb. is kind to do sth.例如：
It is kind of you to say so.=You are kind to say so.
◇ It is necessary (for sb.) to do sth.
常见的这类形容词有：important, necessary, natural, easy, safe, common, normal, hard, difficult, dangerous, impossible, pleasant等。
该句型与上一个同属一种句型。如果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、安全等情况的形容词。例如：
It is important for her to come to the party. =It is important that she (should) come to the party.
◇ We think it important to learn a foreign language.
主句中常用的动词：think, believe, make, find, consider, feel
作真正宾语的三种形式：不定式短语、动名词短语或that引导的宾语从句。
该句型中的it作形式宾语。例如：
We think it our duty to clean our classroom every day. He felt it important learning English well.
They found it difficult that they would finish their work in two days.