资源简介

(共29张PPT)
Unit 2 A Look into the Past
Section A How do we find out about the past
课时3(4a-4c)
1. 掌握并正确运用词汇：ash, unlikely, jade, wealth, Terracotta Army, trade, repair
2. 学会情态动词（must、might、may、could、can等）表示推测的用法
Let’s read and discuss.
A: Look at this old stone knife I found near the river!
B: Are you sure it’s a knife It just looks like a rock.
A: No, look! The edge is sharp. It must have been made by humans.
B: Maybe, but it could be just a broken rock.
A: But it’s too smooth for a natural rock. It might be from the Stone Age.
B: Well, it can’t be from the Stone Age — we don’t have any Stone Age sites around here.
A: You’re right. Perhaps I’m just imagining things!
Let’s read and discuss.
1. What words did the speakers use to show they were not sure
They used could, might, and can’t.
2. What are these words called
They are called modal verbs（情态动词）.
情态动词表示推测的用法
① 情态动词表示推测的基本用法
must 一定 表示有把握的肯定推测
may/might/could/can 也许；可能 表示没有把握的推测
can’t/couldn’t 不可能 表示有把握的否定推测
may not/might not 可能不 表示不太有把握的否定推测
情态动词表示推测的用法
① 情态动词表示推测的基本用法
He must be very happy after hearing the news. 他听到这个消息后一定很高兴。
He may be in his office, but I’m not sure. 他可能在他的办公室，但是我不确定。
— Can the news be true 这消息可能是真的吗？
—No, it can’t be true. 不，它不可能是真的。
That man can’t be your teacher. He’s much taller. 那个人不可能是你的老师。他高得多。
It may not be right, but that’s what I think. 它可能不对，但是那是我的想法。
用法拓展
(1) 情态动词表示推测时，无时态区别，只有语气差别，其语气强弱顺序如下 (由强到弱)：must > can > could > may > might
(2) 含有 must 的句子(must 表推测) 变为否定句时，要用 can’t。
He must be at home. 他一定在家。→ He can’t be at home. 他不可能在家。
② 情态动词在不同时态中表示推测的用法
情态动词+动词原形 表示对现在事情的推测
情态动词＋be＋动词 ing 表示对正在发生的事情的推测
情态动词+have+动词的过去分词 表示对过去情况的推测
This book must be Jim’s because his name is on it.
这本书一定是吉姆的，因为上面有他的名字。
My mother might be cooking in the kitchen.
我妈妈可能正在厨房做饭。
The ground is wet. It must have rained last night.
地面是湿的。昨晚一定下雨了。
Read the sentences. Underline the modal verbs and find out how they are used to express possibilities.
That object must be a horn of some kind.
Researchers now think that may be wrong.
I guess it might be ash.
King Tut’s death could be related to an illness.
That silk clothing can’t be very heavy.
be related to
4a
和……相关
ash.
ash / / n. 灰烬；废墟
4a
very likely
likely
very unlikely
must
_______________________________________________________________________________________
Read the sentences. Underline the modal verbs and find out how they are used to express possibilities.
unlikely
/ n la kli/ adj. 不大可能发生的
may; might; could
can’t
very unlikely (教材P15 4a)
unlikely / n la kli/ adj. 不大可能发生的
It’s unlikely that she’ll arrive before seven.
她不太可能在七点前到达。
He is unlikely to tell lies.
他不太可能说谎。
由“否定前缀 un + likely (adj. 可能发生的)”构成。常用结构 it’s unlikely that… 表示“……不太可能”。
very unlikely (教材P15 4a)
unlikely / n la kli/ adj. 不大可能发生的
词缀学习
un 为常见的否定前缀，常加在某些词前构成其反义词。
necessary adj. 必要的 — unnecessary adj. 不必要的
lucky adj. 幸运的 — unlucky adj. 不幸的
lock v. 把……锁住 — unlock v. 开……的锁；揭开
Complete the sentences with the words in brackets.
4b
1. If she can afford the gold watch, she ________ be poor. (mustn’t, can’t)
2. The jade objects suggest that the owner ________ be a person of great wealth. (can’t, could)
3. In the Terracotta Army, each soldier looks different. The sculptures ________ be the faces of real soldiers. (might, must)
can’t
could
must
/d e d/ n. 玉；翡翠
/welθ/ n. 财产；财富
兵马俑
Complete the sentences with the words in brackets.
4b
4. Some people guess the “horn” ______ have been brought to China through foreign trade because its design is unique to the Middle East. (can’t, might)
5. A: You ______ enjoy being an archaeologist very much. (must, might)
B: You’re right. I love my job.
might
must
be unique to sb./sth. 为某人/某物独有
enjoy doing sth. 喜欢做某事
/tre d/ n. 贸易；买卖
Some people guess the “horn” must have been brought to China through foreign trade because its design is unique to the Middle East. (教材P15 4b)
trade /tre d/ n. 贸易；买卖
trader n.商人
In ancient times, Dunhuang was an important centre of trade.
古时候，敦煌是一个重要的贸易中心。
As years passed, silk became so important that the trade road from China to Europe got its name—the Silk Road.
随着岁月流逝，丝绸变得如此重要，以至于从中国通往欧洲的商路因 此得名——丝绸之路。
Some people guess the “horn” must have been brought to China through foreign trade because its design is unique to the Middle East. (教材P15 4b)
trade /tre d/ n. 贸易；买卖
词义拓展
(1) trade［动词］做买卖；从事贸易
trade (in sth.) with sb. 与某人交易 (某物)
They had years of experience of trading with the West.
他们有数年与西方做生意的经验。
(2) trade［动词］互相交换；以物易物
trade A for B 用 A 换取 B
She traded her posters for his CD. 她以海报换取他的光盘。
Complete the conversation with suitable modal verbs. Why
is repairing ancient books important
4c
may/might
must
James：
Dr Xia：
James：
Those ancient books look in terrible condition. Dr Xia, how long does it take to repair them
Well, it depends. Sometimes, it __________ take years to repair just one book.
That’s a long time! It _________ require a lot of careful work.
状况很差
Complete the conversation with suitable modal verbs. Why
is repairing ancient books important
4c
Dr Xia：
James:
Yes. Each book is a great treasure. Once they are gone, we __________ lose the chance to understand an important part of our history.
That’s true! I think this work is really important. What
__________ I do to become an archaeologist like you in the future
may/might
should/can
lose the chance to do sth. 失去做某事的机会
Complete the conversation with suitable modal verbs. Why
is repairing ancient books important
4c
Dr Xia：
James：
Dr Xia：
Oh, first, you ________ attend university to get the basic knowledge and skills. Then you ________ receive training for a few more years.
It ________ be easy, but I’ll try my best!
Good for you. It is worth the effort.
should
need
can’t
Dr Xia, how long does it take to repair them (教材P15 4c)
repair /r pe (r)/ v. & n. 修理；修补
From books, he learned how to repair clocks, bikes and other things. 他从书中学会了如何修理钟表、自行车和其他东西。(作动词)
The building was in need of repair.
这座大楼需要维修了。(作名词)
既可作动词又可作名词。侧重于修理破损的东西或构造较复杂的东西，如房屋、车辆、电视等。
Dr Xia, how long does it take to repair them (教材P15 4c)
repair /r pe (r)/ v. & n. 修理；修补
词义拓展
repair［动词］弥补，补救
I’m afraid I might lose my best friend, and I’ll try to repair our relationship.
恐怕我可能会失去我最好的朋友，我会努力修复我们的关系。
Dr Xia, how long does it take to repair them (教材P15 4c)
repair /r pe (r)/ v. & n. 修理；修补
典例 根据句意及汉语提示填写单词。
We should ______(修理) the old stages to protect traditional Qin Opera performances.
repair
1. — Look at the lead singer on the stage! Is that our music teacher, Mr. White
—It ____ be him. Mr. White is sitting right next to us in the front row.
A. must B. might C. can’t D. mustn’t
一、选择填空。
C
2. — I’m going to have a visit to the Sanxingdui Museum.
— It ____ be a wonderful experience! Have a good time!
A. must B. can’t
C. need D. may not
一、选择填空。
A
二、完成句子，每空一词。
can’t know
must be
他不可能知道这个秘密。我从未告诉过任何人。
He _____ ______ the secret. I haven’t told anyone about it.
2. 在完成所有那些繁重的工作之后，你一定很累了吧。
You _____ _____ very tired after finishing all of those hard jobs.
情态动词表示推测的用法
表示“一定，必定，肯定”，可能性较大
must
can’t
表示“可能”，可能性不大
表示“不可能”，可能性非常小
can、could、may、 might
情态动词must、might、may、could、can等可以用于表达推测和可能性，但所包含的意义不尽相同。
1. 用情态动词写几句句子，介绍一件历史文物推测它的年代、材质或用途（至少4句话）。
选用以下情态动词中的至少2个：
must be / can’t be
must have done / could have done / might have done
2. 将本课所学内容形成重点笔记。

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