Unit 4 I used to be afraid of the dark 知识考点精讲学案（含解析）

中小学教育资源及组卷应用平台
Unit 4 I used to be afraid of the dark.
课前小测
1、 Remember to think twice ________ you make a decision.
A.and B.before C.so D.unless
2、 I had a good time in the park ________ my parents taught me how to fly a kite.
A.if B.but C.or D.because
3、 You can't swim in the river, ______ it's too dangerous. (　　)
A.and B.so C.but D.because
知识精讲
一、必背词汇
humorous adj. 有幽默感的；滑稽有趣的
silent adj. 不说话的；沉默的
helpful adj. 有用的；有帮助的
score n. & v. 得分；打分
background n. 背景
interview v. 采访；面试n. 面试；访谈
Asian adj. 亚洲的；亚洲人的 n. 亚洲人
dare v. 敢于；胆敢
private adj. 私人的；私密的
guard n. 警卫；看守v. 守卫；保卫
require v. 需要；要求
European adj. 欧洲的；欧洲人的
British adj. 英国的；英国人的
speech n. 讲话；发言
ant n. 蚂蚁
insect n. 昆虫
influence v. & n. 影响
seldom adv. 不常；很少
proud adj. 自豪的；骄傲的
absent adj. 缺席；不在
fail v. 失败；未能（做到）
examination n. 考试；审查
leaf n 树叶
exactly adv. 确切地；精确地
pride n. 自豪；骄傲
grandson n. 孙子；外孙
general adj. 普遍的；常规的；总的 n. 将军
introduction n. 介绍
二、重点词汇
1. humorous adj.
funny, or making you laugh
幽默的；滑稽的
例句： Her latest book is a humorous look at teenage life.
她的新书是对青少年生活的一种幽默审视。
2. interview v.
1). a meeting in which someone asks you questions to see if you are suitable for a job or course
面试；面谈
例句： I had an interview for a job with a publisher.
我参加了一家出版公司的求职面试。
2). to ask someone questions in an interview
采访；对…进行面试；讯问
例句： Who's the most famous person you've ever interviewed on TV
你在电视上采访过的人中谁最有名？
3. require v.
to need something or make something necessary
需要；有赖于；要求；规定
例句：Please call this number if you require any further information.
如需更多信息请拨此电话号码垂询。
4. absent adj.
not in the place where you are expected to be, especially at school or work
（尤指上课或工作）缺勤的，缺席的，不在场的
例句： John has been absent from school/work for three days now.
约翰到现在已经旷课／旷工3天了。
5. general adj.
1). involving or relating to most or all people, things, or places, especially when these are considered as a unit
全体的，总的，普遍的
例句：My general impression of the place was good.
我对这个地方总的印象很好。
2). not detailed, but including the most basic or necessary information
大体的；大致的；笼统的
例句： What he said was very general.
他说得很笼统。
3). an officer of very high rank, especially in the army
（尤指陆军中的）将军
【拓展】
in general
usually, or in most situations
一般来说；通常；在一般情况下
例句：In general, men are taller than women.
一般来说，男人个子比女人高。
三、必背短语
from time to time 时常；有时 turn red 变红
take up 从事 deal with 应对；处理
not any more 不再 worry about 担心
be careful about 关心 hang out 闲逛；出去消遣
a number of 许多；大量的 in public 公开地；在别人（尤指生人）面前
be proud of 为……骄傲；感到自豪 make a decision 做决定
in person 亲身；亲自 take care of 关心
pay attention to 注意；关心 take pride in 为……感到自豪
四、经典句型
1. ---I used to be short.
---I didn’t use to be popular in school.
---我曾经很矮。
---我曾经在学校不怎么受欢迎。
2. --- You used to be short，didn’t you
---Yes, I did. /No , I didn’t.
---你以前很矮，对吗？
---对，我曾是。/不，不是这样的。
3. ---Did he use to wear glasses
--- Yes, he did. /No, he didn’t.
---他以前戴眼镜吗。
---是的,他戴/不戴，他（以前）不戴。
三点剖析
一、考点
1. used to do sth的用法
1). used to是个情态动词，其后接动词原形，意为“过去常常”，指过去经常发生的动作，但现在不再发生了。
2). used to的否定形式有两种：used not to (缩写为usedn’t to)和 didn’t use to；疑问式也有两种：Used +主语+to +动词原形+ ……？或Did +主语+use to +动词原形+ ……？
例句：
You used to have long hair.
你过去留长发。
Did you use to have straight hair
你过去留直发吗？
---Did you use to play the piano
---你过去常常弹钢琴吗？
----No, I didn’t.
---不，我不弹。
2. such的用法
1). such是形容词，常起强调作用。
例句：We’re having such a wonderful time.
我们过得很愉快。
2). 通常状况下，如果such与名词之间还带有形容词，这是不建议使用such，因为会引起歧义。如上文中such a wonderful time，常用so wonderful a time或a time so wonderful。
3). 当句子末尾加上that从句，形成such…that…结构时，表示因为前面提到的原因，引起了某种结果。
例句：It was such a boring speech that I fell asleep.
这个如此乏味的演讲使我睡着了。
二、易错点
1. deal with & do with
1). deal with中deal是不及物动词，用how提问。
例句：I don’t know how I can deal with the matter.
我不知道如何处理这件事。
2). do with中do是及物动词，用what提问。
例句：What have you done with our goods
你怎么样处置了我们的货物？
2. dare的用法
1). dare作及物动词时，意为“敢；胆敢，敢于面对”，后接to do，否定句、疑问句中to可省略。
例句：He doesn’t dare (to) speak to her.
他不敢和她说话。
Does he dare (to) speak to her
他敢和她说话吗？
2). dare作情态动词讲时，没有人称和数的变化，但有时态变化，后接动词原形。
例句：If you dare speak to me like that again, you will be sorry.
如果你再敢那样对我说话，你会后悔的。
used to do sth. 的用法
例题1、 Dale used to _________ to office in his car, but he is used to _________ the bus now.
A.going; taking B.going; take C.go; taking
例题2、 将下列句子译成英语。
我爸爸过去常常开车上班，现在坐公交车了。
________________________________________________
随练1、 Mary saw her elder brother _________ basketball in the playground.
A.plays B.playing C.played D.to play
随练2、 ---It’s Father’s Day today, _________
---Yes, let’s buy a gift for Dad.
A.isn’t he B.doesn’t it C.isn’t it
随练3、 Mr. Lee, wait a moment, please. I don’t want to _________ much of your time. But I really have something important to tell you.
A.give up B.take up C.end up D.set up
随练4、 单词拼写(词汇运用)
根据句意及首字母或汉语提示完成单词。
(1)What parents say and do will i________ their children.
(2)I don't think you will f________ the exam because you work so hard these days.
(3)—What i________ do you like
—I like ants because they are hard-working.
(4)The mother knew ________ (确切地)what her children would do if she left them at home.
(5)Mr. Wang has a lovely ________ (孙子).
随练5、 填空题
(1)Can you hear her ________ (introduce) clearly
(2)The teachers are always ________ (pride) of everything good the students do.
(3)The girl has really ________ (change). Now she is hard-working at all her subjects.
(4)To ________ (we) surprise, he got an A in the English exam.
随练6、 选词填空(词汇运用)
Couplets (联) have been around for about 600 years. It ________ in the Ming Dynasty. People ________ red paper instead of peach wood charms to ________ the Spring Festival couplets. After the Qing Dynasty, the couplets were once ________ popular. Lots of famous couplets appeared. With the development (发展) of the international cultural exchange, the couplets were also ________ to Vietnam, Korea, Japan, Singapore and other ________. The customs of sticking these couplets still ________ now.
Couplets are usually in different ________ and colors. Nice words and sentences are ________ on the couplets. Different couplets are put on doors, walls or windows as symbols of wishes for good ________ and a happy new year.
such的用法
例题1、 He speaks to me in _________ way that I always feel he is insulting me.
A.so a B.such a C.sol D.such
例题2、 根据提示完成句子。
为什么你这么匆忙？
Why are you in _________ _________ _________
随练1、 I’m looking after Tom today. He’s been in my house _________ 8:00 this morning.
A.at B.since C.for D.till
随练2、 Gina used to be _________ and she never spoke in front of the public.
A.outgoing B.noisy C.silent D.humorous
随练3、 补全对话
Mary: Hi, David! I haven't seen you for many years. ________
David: Oh, I have been to London and lived with my parents. They work there.
Mary: I'm very glad to see you again.________
David: Yes, I have. I used to be very quiet. ________
Mary: That's true. Wait a minute! Did you use to play the piano
David:________ But now I prefer sports. And I'm on the football team.
Mary: Wow! People always change.
David: You have changed a lot, too. ________
Mary: Yeah. But now I prefer long hair
David: You look more beautiful with long hair.
Mary: Thanks a lot.
随练4、 句型转换
(1)The sun always rises in the east
The sun rises in the east ________ ________ ________.
(2)He doesn't worry about tests.
He ________ never ________ ________ tests.
(3)Tom has no more interest in playing basketball.
Tom ________ interested in playing basketball________ ________.
(4)It took me three hours to finish all my homework.
I ________ three hours ________ all my homework.
(5)Used he to go to bed late
________ he ________ ________ go to bed late
随练5、 翻译
(1)我们学校变化是如此大。
Our school has changed ________.
(2)朋友们时常来看我。
My friends come to see me ________.
(3)他们不知道如何应对即将到来的暴风雨。
They don't know how ________ the coming rainstorm.
(4)在公 共场合我们必须遵守规则。
We should obey the rules ________.
(5)那个女孩不敢单独待在家里。
The girl doesn't ________ at home alone.
拓展
1、 根据句意及所给汉语提示填写单词。
1. That famous actor is very _________ （幽默的）. Everyone likes him.
2. My younger sister used to be very _________ （沉默的） and she never talked with strangers.
3. She needs to win this point to level the _________ （得分）.
4. Volunteers from different _________ （背景） feel like part of one big family.
5. They _________ （采访） people from all walks of life.
2、 Mr. Lee used to _________ dinner in the restaurant, but now he is used to _________ every meal with his family at home.
A.have; eat B.having; eat C.have; eating
3、 ---Peter, you speak Chinese so well.
---Thank you. I _________ Chinese since I came here in 2013.
A.will learn B.learned
C.have learned D.learn
4、 In our city there _________ a number of cars and the number of them _________ growing larger and larger.
A.are; is B.have; is C.is; are
5、 It took me almost a whole day to_________ so many emails.
A.deal with B.cut in
C.cheer for D.run out
6、 Mr. Green is very _________. He is good at telling jokes in class and we all like him very much.
A.kind B.humorous C.serious D.polite
7、 根据句意及所给汉语提示填写单词。
1. A _________ （警卫） stopped me and asked me to show him my passport.
2. I don’t know the man who is giving a _________ （演讲） over there.
3. It is a _________ （私人的） conversation. It’s none of your business.
4. You shouldn’t speak so loudly in _________ （公共的） places.
5. It’s very _________ （有帮助的） to discuss your problem with your parents.
8、 完形填空
My husband died and I became very angry. I hated being alone. One day, as I was ___1___ down a busy street, I suddenly noticed a beautiful new fence (栅栏)around a house. The ___2___ still smelled of fresh paint.
“Hello!” I came up and said to a ___3___ in the back garden, “I came to see the fence, it's so beautiful!”
“Oh! The fence is not there for me,” the lady explained to me in a calm voice,”I live alone.
___4___ so many people pass by every day, I think they may be pleased to see something really wonderful. ___5___ stop like you and come up to have a chat.”
“But weren't you ___6___when they expanded (拓宽)the road and everything changed so much ” “Change is part of life and takes part in making us who we are. When something we do not like happens to us, we have___7___choices to become a bitter (痛苦的)person or to become a better person.”
Her reply changed my life, I carefully left the gate open and drove on ___8___a new feeling inside me. I could not tell ___9___it was, but I could feel the thick stone wall around my ___10___ heart breaking off.
9、 任务型阅读
阅读短文,完成小题。
If you think you're too shy and want to be a little bit braver, try the following. You can make it.
____①____There's no need to hide(隐藏)it. When they get to know you're a shy kid, they'll understand you better. This also helps you feel more at ease in talks.
____②____When you smile, people think you are friendly and easy to talk to. Remember that other people also have feelings and most people will stay away from an angry-looking face.
____③____If you find it hard to start talks, say something nice about people around you. Think about how great you feel when someone says something nice to you. Doesn't it make you want to keep talking to that person
____④____Think more about ways to enjoy the party or the game. Don't waste time worrying about your looks or whether people like you or not.
Take one small step at a time. Each time after you say “Hi” or smile at someone for the first time, say to yourself “You did it!” Or it could be something bigger, like buying yourself an ice cream.
Keep trying and one day you'll never be “shy” when you talk to others.
(1)The phrase “make it” means “________”.
(2)把下面方框中的四个句子放回文中①________②________③________④________处。
A．Learn to be a good talker.
B．Get your attention elsewhere.
C．Tell people you're shy.
D．Try to smile more.
(3)将画线句子翻译成汉语。
(4)Which sentence has the same meaning as “people will stay away from an angry-looking face”
A．Some people want to make others angry.
B．People don't want to talk to the people who look angry.
C．Angry people don't want to talk with others.
D．Don't look at angry people.
10、 写作题：书面表达
假设你是Tony Li,在英国一所中学就读已大约一年,需要找一位家庭教师。条件要求如下表所示,请你向你的老师Mr. Roger Fike写一封邮件,请他帮忙。
写作要求：(1)文体格式正确,信息完整,内容合理；(2)句子结构准确,篇章结构连贯,字数不少于80个单词；(3)文中不能出现真实姓名和学校名称；
提示词：家庭教师tutor; 标准英语standard English
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
答案解析
课前小测
1、
【答案】 B
【解析】 暂无解析
2、
【答案】 D
【解析】 暂无解析
3、
【答案】 D
【解析】 because因为,后跟从句．but但是．so所以．and和．根据你不能在河里游泳,因为它太危险了．
Unit 4 I used to be afraid of the dark.
used to do sth. 的用法
例题1、
【答案】 C
【解析】 考察固定搭配。used to 表示“以前常常”，后跟动词原形；be used to 表示“习惯于”，后跟动名词，故选C。
例题2、
【答案】 My father used to drive to work, but now he takes the bus.
【解析】 考察固定搭配。used to 表示“以前常常”，后跟动词原形，而后面半句表示“现在……”，应该用一般现在时态。
随练1、
【答案】 B
【解析】 考察固定搭配。see sb doing sth意为“看见某人正在做某事”，故选B。
随练2、
【答案】 C
【解析】 考察反意疑问句的结构。根据陈述部分的It’s 可推断，反意疑问部分要用isn’t it，故选C。
随练3、
【答案】 B
【解析】 考察固定搭配。根据语境可知，我不想占用你太长时间，因此所缺词组为take up，故选B。
随练4、
【答案】 (1)influence
(2)fail
(3)insects
(4)exactly
(5)grandson
【解析】 (1)父母亲所做所言将会______他们的孩子。influence影响(动词),will后跟动词原形。
(2)我认为你将不______考试因为你这些天学校(工作)这么努力。fail失败(动词),will后跟动词原形。
(3)你喜欢什么______ --我喜欢蚂蚁因为它们很勤劳。insect昆虫(名词)。根据助动词do可知要用可数名词复数。
(4)确切地exactly。
(5)孙子grandson 。根据a可知要填可数名词单数。
随练5、
【答案】 (1)introduction
(2)proud
(3)changed
(4)our
【解析】 (1)introduce介绍(动词),her后跟名词。
(2)pride骄傲,自豪(名词),be proud of以......为荣。
(3)change改变(动词/名词)。根据has可知此句为现在完成时,has +动词过去分词。
(4)we我们(人称代词主格)。根据短语 to one's surprise令某人惊讶的是,可知此处应填形容词性物主代词。
随练6、
【答案】 started；used；make；widely；introduced；countries；remain；shapes；written；luck
【解析】 country国家, remain保留, write书写, luck运气, start开始, make制作/使, use用, widely广泛地, shape形状, introduce介绍
(1)句意：它开始于明朝。根据上文Couplets (联) have been around for about 600 years. 对联已经有600年了,可知对联开始于唐朝,通篇时态为一般过去时,动词开始start的过去式为started。
(2)句意：人们使用红纸来代替桃木符来制作对联。动词使用use的过去式为used。
(3)句意：人们使用红纸来代替桃木符来制作对联。制作为make, to后接动词原形构成动词不定式短语作目的状语。
(4)句意：清朝后,对联一度广受欢迎。流行的popular为形容词,副词修饰形容词,widely修饰形容词popular,意为“广受欢迎”。
(5)句意：对联也被介绍到越南、韩国、日本、新加坡...。根据对联the couplets 和动词介绍introduce存在动宾关系可知,本句应用一般过去时态的被动语态was/were+过去分词。introduce的过去分词为introduced。
(6)句意：对联也被介绍到越南、朝鲜、日本、新加坡和其他国家。根据Vietnam, Korea, Japan, Singapore 可知,都是国家,用country。other后接可数名词复数,country的复数形式为countries。
(7)句意：贴对联的习俗依旧保留到现在。根据The customs of sticking these couplets still ________ now.可知,贴对联的习俗保留到了现在,保留用remain。
(8)句意：对联通常有不同的形状和颜色。根据colors颜色可知,前面的空格须填写与之并列的shapes形状。
(9)句意：好词好句被写在对联上。主语Nice words and sentences好词好句和动词写构成动宾关系,可知本句应用被动语态be+过去分词,动词write的过去分词为written。
(10)句意：不同的对联作为好运或者是新年快乐的象征被贴在墙上和窗户上。good luck为固定搭配,意为“好运”。
such的用法
例题1、
【答案】 B
【解析】 考察such的用法。句意为：他用那种方式跟我说话，总让我觉得他是在侮辱我。way是单数可数名词，所以要用such a way，故选B。
例题2、
【答案】 such a hurry
【解析】 考察such的用法。hurry作名词，in a hurry意为“匆忙地”；such修饰单数名词时应位于不定冠词前面。
随练1、
【答案】 B
【解析】 考察介词。根据本题语境“他就从今天早上8点就一直在我家”可知，应该用现在完成时，所缺介词为since，故选B。
随练2、
【答案】 C
【解析】 考察形容词辨析。根据语境可知吉娜以前很沉默，从不在人们面前讲话，所缺词是silent，故选C。
随练3、
【答案】 FDCAB
【解析】 (1)根据回答I have been to London。应该问你去哪里了？
(2)Yes是回答一般疑问句或反义疑问句,D是反意疑问句。
(3)根据上句I used to be very quiet.可知继续描述自己的情况。上句说我过去安静,C句说我现在外向。
(4)对一般疑问句的回答用Yes/No。
(5)根据回答But now I prefer long hair.可知以前是短发。
随练4、
【答案】 (1)all；the；time
(2)is；worried；about
(3)isn't；at；all
(4)spent；doing
(5)Did；use；to
【解析】 (1)always总是,同义短语是all the time。
(2)worry about担心,同义短语是be worried about。
(3)no more不再,同义短语是not...at all；not和is进行缩写。
(4)take表示花费时间,主语是it, 主语是指人时,花费用spend; spend doing sth.而且是一般过去时。
(5)句意：他以前常常晚睡吗？同义表达为used to do 的一般疑问句。
随练5、
【答案】 (1)so much
(2)from time to time
(3)to deal with
(4)in public
(5)dare to stay
【解析】 (1)如此大 (修饰动词change变化)so much。
(2)时常from time to time。
(3)应对deal with。此题考查特殊疑问词+动词不定式做宾语的结构。
(4)在公共场合in public。
(5)敢：dare to, doesn't 后跟动词原形。呆(在家)stay (at home)。
拓展
1、
【答案】 1. humorous
2. silent
3. score
4. backgrounds
5. interview
【解析】 考察本课词汇的应用，需注意联系语境、时态、人称的数及名词的单复数。
2、
【答案】 C
【解析】 考察固定搭配。used to 表示“以前常常”，后跟动词原形；be used to 表示“习惯于”，后跟动名词，故选C。
3、
【答案】 C
【解析】 考察动词时态。根据since I came here in 2013可知，时态要用现在完成时，故选C。
4、
【答案】 A
【解析】 考察主谓一致。在本题中，和a number of 搭配的be动词是are，和the number of搭配的be动词是is，故选A。
5、
【答案】 A
【解析】 考察固定搭配。根据语境可知，我几乎花了一整天来处理邮件，因此所缺词组为deal with，故选A。
6、
【答案】 B
【解析】 考察形容词辨析。根据题干中“他善于讲笑话”可知，格林先生很幽默，故选B。
7、
【答案】 1. guard
2. speech
3. private
4. public
5. helpful
【解析】 考察本课词汇的应用，需注意联系语境、时态、人称的数及名词的单复数。
8、
【答案】 CDCAB DBADC
【解析】 本文讲述作者在丈夫去世之后一直郁郁寡欢。一次路过一个房子,看见周围围着的漂亮栅栏,作者停下来跟房主聊天,发现栅栏并不是房主的,而是人们把路扩宽之后建的,这很大程度上影响了房主的生活。但是房子的主人并没有生气,而是选择坦然面对。与房主的对话解开了作者的心结,让作者有了一种新的心情面对生活。
(1)句意：我丈夫去世了,我很生气。我讨厌一个人。一天当我开车走在一条繁华的街上时,我注意到一个房子周围漂亮的栅栏。walk走；ride骑；drive驾驶；run跑。从文章中最后一段的第二句话可知,作者是开着车的。
(2)句意：栅栏仍还有一种新鲜的油漆的味道。street街道；paint油漆；house房子；fence栅栏。联系上下文语境可知,此处选fence,意为“栅栏,围墙”。
(3)句意：我走上前,跟后院的一位女士打招呼。由下文the lady explained to me in a calm voice可知,此处应是lady。
(4)句意：但是每天有这么多人经过,我想他们也许很高兴看到很好的东西。根据语境可知,此处表示转折关系。
(5)句意：几个像你这样的人停下来过来聊天。few几乎没有；a few几个；一些。联系上下文可知,此处表示肯定。
(6)句意：但是他们把路扩宽,一切变化这么大,你不伤心吗？由下文中的a bitter (痛苦的)person可知,答案选sad难过的,悲伤的。
(7)句意：当我们不喜欢的事情发生了,我们有两个选择：成为痛苦的人还是成为更好的人。由后文可知,这里应该指“两个选择”。
(8)句意：她的回答改变了我的生活,我小心地让门开着,带着一种新的感觉。with此处表示“带着,携带”。
(9)句意：我说不清那是什么。根据语境可知,此处选what,引导宾语从句。
(10)句意：但是我能感到,我的生气的心周围的厚厚的石头粉碎了。根据第一句中“I became very angry”。
9、
【答案】 (1)succeed
(2)C；D；A；B
(3)这(告诉人们你很害羞)也有助于让你在交谈中感到更加自在。
(4)B
【解析】 本文介绍克服羞怯心理的几种方法。
(1)词义猜测。根据句意：如果你觉得你太害羞而想变得勇敢一点,尝试下面的方法,你会成功的。所以make it意思是“成功”。
(2)① 细节理解题。根据When they get to know you're a shy kid… “当他们知道你是一个害羞的孩子……”,可知该空与shy有关。
② 细节理解题。根据下文中When you smile, people think you are friendly and easy to talk to.,可知此空与微笑有关。
③细节理解题。根据If you find it hard to start talks, say something nice about people around you. Think about how great you feel when someone says something nice to you.可知,与此相关的只有A项。
④推理判断题。根据Think more about ways to enjoy the party or the game. Don't waste time worrying about your looks or whether people like you or not. 可知谈论的是如何进行注意力转移。
(3)句子翻译：This这, also也, helps you帮助你, feel感觉, more更多的, at ease轻松的；自在的, in talks在谈话中。
(4)people will stay away from an angry-looking face 意为：人们将会远离满脸怒容的人。A项意为：一些人想让别人生气；C项意为：生气的人不想和别人说话；D项意为：不要看生气的人。A、C、D项均与题干所给句子的意思不符。只有B“人们不想和看起来生气的人交谈”是正确答案。
10、
【答案】 Dear Mr. Fike,
I've been here for almost a year and I find the life is not easy for me. I think I need a tutor. Would you please help me find one
First, the tutor should be a beautiful girl or woman, 20-25 years old. She can be either a college student or an English teacher from middle school or primary school. Second, I hope the tutor is patient and helpful, who loves reading and travelling. Third, most importantly, she should be able to speak standard English and be familiar with the English history and geography.
With best regards.
Yours,
Tony Li
【解析】 这是一封电子邮件,和书信的格式基本一样。注意要先写简单介绍自己的情况,再列出所需的条件；可用First/Second/Third等词,层次分明。以第一人称为主,适当使用第三人称。可用句式：She can/is able to/is supposed to...注意使用所给的提示词。