2019英语新一线同步北师大必修四讲义：UNIT 10 SECTION Ⅴ GRAMMAR WORD版含答案.doc

1、Section_Grammar单元语法项目(一)不定代词语法图解探究发现Charles believes that many people want to earn a lot of money so that they will not have any worries.However, most people never make much money.A lot of people are determined to become a millionaire.But do all millionaires find the happiness that they thought they

2、 would get when they achieve their goals?They are hardworking to get all that money.There is a small garden outside with a few fruit trees.He has discovered that having a little money makes you free.Both of his eyes are hurt.Either answer is correct.Hopefully, neither of these things will happen.我的发

3、现(1)many修饰复数可数名词，如句；much修饰不可数名词，如句；a lot of既可修饰可数名词，也可修饰不可数名词，如句和句。(2)all既可修饰复数可数名词，如句；也可修饰不可数名词，如句。(3)a few修饰或指代复数可数名词，如句；a little修饰或指代不可数名词，如句。(4)both意为“两者都”，作主语时谓语动词用复数，如句；either意为“两者当中任意一个”，作主语时谓语动词用单数，如句；neither意为“两者都不”，作主语时谓语动词常用单数。一、不定代词概述1不定代词是不指明代替任何特定名词的代词，具有名词和形容词的性质，并有可数和不可数、单数和复数之分。常见的不

4、定代词有all, both, each, every等，以及含有some， any，no等的复合不定代词，如anybody，something, none。不定代词在句中作主语、定语、宾语和表语。“Where there is a will, there is a way” is an old proverb which almost everyone knows, but not all understand it so well. (2014山东高考满分作文)“有志者事竟成”这句古老的谚语几乎人人皆知，但并不是所有的人都对它理解的很透彻。I badly need someone to he

5、lp me with my oral English, at which lots of Chinese students are bad. (2015四川高考书面表达)我急需要有人来帮助我学习英语口语，英语口语是许多中国学生很不擅长的。A smile costs nothing, but gives much. (2014重庆高考写作一)微笑什么都不会花费，但却带来很多。I asked all the children and each told a different story.我问过所有的孩子，每个人的说法都不一样。2复合不定代词作主语时谓语动词用单数，都不能接of短语；但分开写的so

6、me one, any one, every one可与of连用。no one不与of连用，但none可与of连用。I argue that every one of us should try our best to help those in need. (2014重庆高考写作一)我认为我们每个人都应竭尽全力去帮助那些需要帮助的人。None of us has/have been to Beijing so far.到目前为止，我们中没有一个人去过北京。No one expects you to be perfect, but we do expect you always to do y

7、our best.没人指望你完美无缺，但我确实希望你尽力而为。二、几组常见不定代词的区别1many, much, few, a few, little, a little意义区别许多有点/些(表示肯定)几乎没有(表示否定)可数manya fewfew不可数mucha littlelittleMy math used to be poor and I failed many times in the exam. (2014福建高考书面表达)我的数学曾经很差，我在考试中失败过很多次。There has been much gossip in commercial circles as to his

8、 resignation.关于他的辞职，在商界一直有很多流言蜚语。A few days later, the problem was really solved. (2014北京高考书面表达二)几天之后，这个问题真的被解决了。I think it is natural, for a little stress can be good for the exams. (2014四川高考书面表达)我认为这是很正常的，因为少许压力可能对考试有好处。What he says suggests that he cares little about others pain or trouble, even

9、if theyre his friends. (2014重庆高考写作一)他所说的表明了他几乎不关心他人的痛苦和麻烦，即使他们是他的朋友。即时演练1选词填空Many of the high school students are studying hard to enter Peking University, but only_a_few_of them are lucky enough.There is little time left, but we still have much to do.There is only a_little oil left, but we still ha

10、ve many miles to travel to get there.Living in Shanghai for a_few years, yet he has made few friends there.2another, other, the other, others, the others不定代词词义用法another另一个，又一个用于三者或三者以上中的另一个，后接可数名词单数other其他的，另外的后接复数名词或不可数名词the other两者中的另一个常与one连用，构成one .the other .结构others泛指别的人或物是other的复数形式不能作定语，常构成s

11、ome .others .结构；other可数名词复数othersthe others特指其余的人或物是the other的复数形式，常构成some . the others .结构；the other可数名词复数the othersFirstly, I have always been interested in reading books. Secondly, Id like to share my books with others as well. (2015重庆高考写作二)首先，我对读书一直很感兴趣。其次，我也很愿意和其他人分享我的书籍。His parents both work i

12、n a hospital. One is a doctor and the other is a nurse.他父母都在一家医院工作。一个是医生，一个是护士。One of my brothers lives in America; the others are all in my hometown.我的一个兄弟住在美国，其他的都在家乡。Please give me another ten minutes.请再给我十分钟。即时演练2选词填空As far as Im concerned, it is not wise for us to be addicted to playing with sm

13、art phone because we may ignore other important things in life, such as friendship and taking physical exercise. (2014重庆高考写作一)Some of the boys in our class are standing and the_others are sitting round them.He is not free this weekend. Can we make it another day?(2015陕西高考改编)To warm himself, the sail

14、or sat in front of the fire rubbing (摩擦) one bare foot against _the_other.(2014福建高考改编)In some countries, people eat with chopsticks, while in others,_knives and forks.3all, none, both, neither, either, each, every不定代词词义用法all全部(三者或三者以上)指代或修饰可数名词或不可数名词均可；可接 of 短语none一个/点都没有(三者或三者以上)指人指物均可；可接 of 短语；否定词

15、both两个都指代或修饰可数名词或不可数名词均可；可接 of 短语neither两者都不指人指物均可；可接 of 短语；否定词either任意一个(两者之间)指人指物均可；可接 of 短语each每一个(两者或两者以上)指代或修饰可数名词；可接 of 短语every每一个(三者或三者以上)修饰可数名词；不可单独使用，不可接 of 短语As a matter of fact, none of us can live alone in society.(2014重庆高考写作一)事实上，我们没有人能够独自一个人生活在这个社会上。 (none表示三者或者三者以上都不)Shed lived in Lon

16、don and Manchester, but she liked neither and moved to Cambridge.(2014四川高考改编)她曾在伦敦和曼彻斯特住过，但她都不喜欢，于是迁居到剑桥。(neither 表示两者都不)Each of her sons gave her presents for Mothers day.每个儿子每人都给了她母亲节礼物。(each 表示两者或者两者以上当中的每一个，可以接 of 短语，也可以单独使用)Every student can develop healthily now.现在每个学生都能健康发展了。(every 表示三者或者三者以上

17、当中的每一个，不可接 of 短语，不可以单独使用)Both of the plans sound reasonable.这两个计划听起来都合情合理。(both 表示两者都)Either of the two plans sounds reasonable.这两个计划听起来都合情合理。(either 表示两者中任何一个)即时演练3选词填空(2015四川高考改编)Niki is always full of ideas，but none is useful to my knowledge.(2015福建高考改编)The research group produced two reports bas

18、ed on the survey，but neither contained any useful suggestions.(2015四川高考改编)Besides, Chinese has always been my strength among all the subjects.(2015陕西高考改编)Successfully, I have lent a helping hand to her in several English activities of my class, which have been appreciated by both teachers and my cla

19、ssmates.(2014江西高考改编)When shall I call, in the morning or afternoon? Either. Ill be in all day.There is a special red button in each of the shoes.4it, one, the one, ones, the ones, that, those不定代词用法it代替前面出现的可数名词单数，前面提到的某件事情、某种情况、某个动作以避免重复，也可以代替动词不定式短语、名词短语等one用来代替前面提到的可数名词单数或 a/anadj. 可数名词单数，为泛指，指“同类

20、当中的某一个”the one用来代替前面提到的可数名词单数，为特指ones用来代替前面提到的可数名词复数，为泛指the ones用来代替前面提到的可数名词复数，为特指，相当于 thosethat代替前面提到的“the不可数名词”，也可代替前面提到的“the可数名词单数”those代替前面出现的可数名词复数，避免重复，且表示特指，后有定语修饰，可与 the ones 通用I lost my pen yesterday. Have you seen it?Look at the one over there.我昨天丢了钢笔，你看见了吗？(it 指代我昨天丢的钢笔，为同名同物)看看那边那支。(the

21、 one 特指那边那支钢笔)I want to own a house, one that is not big but very convenient.我想拥有一座房子，不大但很方便的房子。(one 指代 a house, 为同名异物，泛指同类当中的某一个)I do not like scientific books. I like story ones.我不喜欢科幻书，我喜欢故事书。(ones 指代 books，为泛指)The weather in Hainan is warmer than that in Tianjin.海南的天气比天津的暖和。(that 指代不可数名词 the wea

22、ther, 后有介词短语 in Tianjin 修饰)The film is not as interesting as that/the one we saw together last week.这部电影不如我们上周一块去看的那部有趣。(that/the one 指代可数名词 the film，后有从句 we saw together last week 修饰)The houses made of stone are generally stronger than those/the ones made of wood.用石头砌的房子通常比用木头造的结实。(those/the ones 指

23、代复数名词 the houses，后有 made of wood 修饰，为特指)即时演练4选词填空(2015浙江高考改编)How would you like it if you were watching your favorite TV program and someone came into the room and just shut it off without asking you?(2015天津高考改编)The quality of education in this small school is better than that in some larger schools

24、. The cars of the rich are generally more expensive than those/the_ones of the poor.There is only one watch of the type in the shop, so I want to buy it for her.This book is not so useful as that/the_one I bought yesterday.用适当的不定代词填空1(2016浙江高考改编)In many ways, the education system in the US is not ve

25、ry different from that in the UK. 2(2015重庆高考改编)The meeting will be held in September, but nobody knows the date for sure.3(2014山东高考改编)Susan made it clear to me that she wished to make a new life for herself. 4(2014安徽高考改编)You can ask anyone for help. Everyone here is willing to lend you a hand. 5(201

26、4天津高考改编)Our school lies in Tianjin City, which is beautiful. In autumn, its neither too hot nor too cold.6To stay awake, he finished a cup of coffee and ordered another.7. (2015广东高考读写任务)Finally they will become active learners rather than passive ones.8(2015重庆高考写作二)Ive learnt that your website is or

27、ganizing an activity, and there are two kinds of participating ways. One is called “wild release (自由分享)” and the_other “controlled release (定向分享)”9Some boys are planting trees and others are watering them.10Stephen Hawkings theory is so difficult that few people can understand and accept it.11Nothin

28、g is impossible if you put your heart into it.12She had few friends, and was generally not functioning up to her potential.单句写作1(2015浙江高考书面表达) Once we were left to decide_either_to_have_a_picnic_in_a_park_or_go_to_a_museum (要么在公园里野餐，要么去博物馆). 2(2015陕西高考书面表达) As an outgoing student, I_am_good_at_commu

29、nicating_with_others (我很擅长与其他人交流), which makes me feel confident about this position.3(2015广东高考读写任务) They_wont_help_the_others (他们不去帮助其他同学), so I explain to them that when_you_help_the_other_classmates (当你帮助其他同学时), you can also revise the knowledge at the same time and you_are_sure_to_benefit_from_i

30、t (你一定会从中获益)4. (2015广东高考读写任务) When Sally found there_were_so_many_problems_among_her_new_students (在她的学生中有如此多的问题), she didnt lose heart.5(2015广东高考读写任务) Lots of students in our class spend a large amount of time doing homework, but_show_little_interest_in_physical_exercise_and_afterclass_activities (

31、对体育锻炼和课外活动几乎不感兴趣)6(2015陕西高考书面表达)Secondly, as an outgoing and warmhearted girl, I_am_always_ready_to_help_everyone (我总是乐于帮助每一个人)7(2015浙江高考书面表达) As a result, they agreed to my advice, and everything_went_well_as_planned (按计划一切进展顺利)8(2015浙江高考书面表达) Because many students going to the ward would not_only_

32、waste_much_time_but_also_make_a_lot_of_noise (不仅浪费了许多时间，而且还会制造大量噪音), which could disturb_both_the_student_and_other_patients (既打扰了这位学生又打扰了其他病人)单元语法项目(二)不 定 式语法图解探究发现To get there by bike will take us half an hour.Would you like to be a millionaire?Her job is to take care of the children in the kinder

33、garten.The soil contains materials to keep the natural balance of the area.On land with rich soil, local farmers can grow crops to make a living.The doctor advised the patient to give up smoking.She asks to be treated equally.Mary seems to be thinking deeply.She is said to have studied abroad last y

34、ear.我的发现(1)不定式在下列句子中的句法功能是：句作主语；句作宾语；句作表语；句作定语；句作状语；句作宾语补足语。(2)在下列句子中不定式使用的时态、语态形式是：句为被动语态；句为进行时态；句为完成时态。(3)根据以上可归纳出，不定式在句中可作主语、宾语、表语、定语、状语和宾语补足语；不定式既有时态的变化，也有语态的变化。一、动词不定式的基本结构动词不定式是一种非谓语动词形式，其结构为“to动词原形”，其中 to 不是介词，而是动词不定式的符号，称为小品词。动词不定式没有人称和数的变化，其否定形式是在 to 前加 not。 动词不定式主要有三种结构模式：1带 to 或不带 to: (to

35、) do sth.Our teacher asks us to be grateful to our parents.老师叫我们要感恩父母。I saw a stranger enter our community.我看见一个陌生人进了我们社区。He told me not to move until he finished the drawing.他告诉我他画完了画我再动。2疑问词不定式：how/when/what . to do sth.No one knows for sure what to expect in the future.没人能确切地知道将来会发生什么。3带逻辑主语的不定式：

36、for/of sb. to do sth.It is wise of you to give up smoking.你戒烟是明智的。二、动词不定式的时态和语态时态语态意义例句主动被动一般时to doto be done与谓语动作同时发生或发生在谓语动作之后I hope to meet you again. 我希望再次见到你。进行时to be doing 表示谓语动作发生时，不定式表示的动作正在进行He pretended to be listening to the teacher carefully. 他假装在认真地听老师讲课。A new shopping mall is reported

37、to be being built in the city at present.据报道该市目前正在建造一家新商场。完成时to have doneto have been done表示不定式的动作发生在谓语动作之前I am sorry to have kept you waiting so long.很抱歉让你久等了。完成进行时to have been doing发生在谓语动作之前并且一直到谓语动作发生时仍在进行They are said to have been working in Tibet for 20 years.据说他们已经在西藏工作了20年。即时演练1用所给词的适当形式填空She

38、 seems to have_heard (hear) about this matter.Hes said_to_go (go) abroad next month.He pretended to be_reading (read) when I came in.She is said to have_been_working (work) on the problem for many years.He was said to have_been_told_(tell) about the news.三、不定式的句法功能1不定式作主语不定式作主语时，表示具体的行为或将来的行为。不定式作主语

39、时谓语用单数；有时也可用 it 作形式主语，而将不定式后置。To remove all the books will take us half an hour.It will take us half an hour to remove all the books.搬走所有这些书要花费我们半个小时的时间。常见的带形式主语it的句型有：(1)It is/was形容词(of/for sb.) to do sth.It is good for us to do morning exercises.做早操对我们有益。It is stupid of her to make such a mistake.

40、她真蠢，犯这样的错误。名师点津在该句型中，如果形容词是形容人的品质的， 即sb.和adj.有主系表关系时，sb.前用of。常见的形容词有foolish/kind/nice/careless/wise/silly/clever/stupid/rude 等；如果句中形容词修饰动词不定式时，sb.和adj.构不成主系表关系时，sb.前用for，常见的形容词有easy/difficult/hard/important/dangerous/possible/necessary等。(2)It is a pleasure/pity/pleasant thing/an honour .to do .In th

41、e end, kids as we are, its our duty to control ourselves, which will greatly help our lives and study.(2014安徽高考满分作文)最后，尽管我们是孩子，但是自控是我们的职责，它会极大地帮助我们的生活和学习。(3)It takes sb.some time/money / energy to do . It took them about half an hour to work out the difficult maths problem.他们花了大约半个小时的时间才解出这道数学难题。即时演

42、练2(1)单句改错It is nice for you to rescue me from the fire in time.forofThe room is comfortable for us to live._livelive_inThis machine is very easy to be operated. Anybody can learn to use it in a few minutes. be_operatedoperate(2)完成句子It took years of work_to_reduce_the_industrial_pollution_and_clean_t

43、he_water.减少工业污染和清洁河水花费了好几年的时间。Its standard practice for a company like this one_to_employ_a_teacher.对于像这样的公司雇佣老师是非常标准的做法。It_is_impossible_for_him_to_get_away_with_it if he cheats in the exam.他如果在考试中作弊，是不可能逃脱惩罚的。2不定式作表语不定式在系动词后作表语，往往说明主语的具体内容，且含将来意义。My purpose is to point out the difficulties of fini

44、shing the job.我的目的是指出完成这份工作的困难。即时演练3完成句子The engine just wont start.Something seems to have gone wrong with it.引擎发动不起来了。看起来好像出了什么毛病。What he hoped was to_be_admitted_into_the_university.他所希望的是能被这所大学录取。Our aim is to_achieve_the_task_in_six_months.我们的目标是在6个月之内完成这项任务。3不定式作宾语(1)有些动词只能跟不定式作宾语，如 agree, ask,

45、 aim, attempt, choose, decide, demand, expect, fail, help, learn, manage, offer, plan, prepare, pretend, promise, refuse, hope, wish等。I decided to buy a walkman to learn English.我决定买个随身听来学英语。His brother wished to win the first prize.他哥哥希望获得头等奖。(2) 不定式作宾语时，如带有宾语补足语，则要把不定式(真正宾语)放到宾语补足语的后面，用it作形式宾语，构成“

46、动词it宾补不定式”结构。能用于此结构的动词有think, make, feel, find等。The two girls are so alike that strangers find it difficult to tell one from the other.这两个小女孩长得如此相像，以至于陌生人觉得很难把她们区分开。I think it possible to get on well with him.我认为有可能跟他和睦相处。名师点津不定式用在介词but(除了), except, besides后面时，如果这些介词之前有行为动词do的各种形式，那么这些介词后的不定式不带to，否则

47、要带to。If you decide to study in America, you have no choice but to improve your English greatly.如果你打算去美国学习，除了显著提高英语水平外别无选择。There is nothing to do except wait till it stops raining.没办法，只好等雨停了。即时演练4单句语法填空(2015陕西高考改编)After receiving the Oscar for Best Supporting Actress，Anne Benedict went on_to_thank (t

48、hank) all the people who had helped in her career.(2014全国卷改编)He refused to_stop (stop) until we reached the next stop.I have no choice but to_go (go). I find it difficult to_keep (keep) a balance between work and play.4不定式作宾补(1)不定式可作 ask, allow, permit, persuade, encourage, expect, order, tell, requ

49、ire，advise, teach, like, wish, force, invite 等动词的宾补，形式为：动词宾语宾补(不定式)。在被动语态中，宾补变主补。Would you like me to give your regards to Mary?要让我替你向玛丽问好吗？I want you to understand the whole passage clearly.我想让你清楚地理解整篇文章。(2)不定式位于let, make, have，feel，look at，see, notice, watch, observe，hear, listen to等词(短语)后面作宾补时不定式

50、符号to须去掉。但当宾补变为主补时，不定式符号to必须加上。(归纳为：一感feel ；二听hear, listen to；三让let, make, have；五看see, look at, notice, watch, observe；半帮助help)I saw him enter the room.我看见他进了房间。He was seen to enter the room.有人看见他进了房间。(3)不定式可用于 with 复合结构中作宾补。在该结构中不定式表示将来，并且用主动表示被动。With her husband to help her, she believes she can wo

51、rk it out.有她丈夫的帮助，她相信能解决这个问题。即时演练5单句语法填空(2014江西高考改编) He is thought to_have_acted_(act) foolishly.Now he has no one but himself to blame for losing the job.With a lot of difficult problems_to_settle (settle), the newly elected president is having a hard time.Paul doesnt have to be made_to_learn (lear

52、n). He always works hard.The teacher told them not_to_make (not make) so much noise.5不定式作定语(1)不定式通常放在被修饰词之后，往往表示未发生的动作。The weather will keep warm in the days to come.在未来几天内，天气将继续保持暖和。We have some problems to solve.我们有一些问题需要解决。(2)中心词是序数词、形容词最高级以及 the last, the only 等，或被这些词修饰时，用不定式作定语。Zhang Jian is th

53、e first Chinese to swim across the Bohai Sea.张健是第一个横渡渤海的中国人。He was the only one to finish the task on time.他是唯一一个按时完成任务的人。(3)抽象名词 time, way, reason, chance, courage, opportunity, ability 等和不定代词 something, nothing, little 等的后面常用不定式作定语。A subway is an effective way to solve traffic problems in a big ci

54、ty.地铁是解决大城市交通问题的有效方法。名师点津作定语的不定式中的动词如果是不及物动词，或者不定式所修饰的名词或代词是不定式动作的地点、工具等，不定式后面须有相应的介词。I use a pen to write with.我用一支钢笔写字。He is looking for a house to live in.他正在找房子住。即时演练6单句语法填空(2015湖南高考改编)Sometimes I act as a listening ear for fellow students_to_talk_ (talk) over what is bothering them.(2014北京高考改编)

55、 There are still many problems to_be_solved (solve) before we are ready for a long stay on the Moon.(2013北京高考改编)Volunteering gives you a chance_to_change (change) lives, including your own.(2013四川高考改编)The airport to_be_completed (complete) next year will help promote tourism in this area.6不定式作状语(1)作

56、目的状语：可位于句首或句末，其前可加 in order/so as, 但 so as to 不可位于句首。I got up early (in order/so as) to catch the 6：30 train.我早起是为了赶那趟六点半的火车。(2)作原因状语：主要用在表示喜怒哀乐等情感的形容词或过去分词后。Im glad to hear your mother is well again.听说你妈妈好了我很高兴。(3)作结果状语：常用only to do(表示出人意料或意想不到的结果)或too .to(太而不能)来表示。I hurried to the post office, onl

57、y to find it closed.我急忙赶到邮局，结果发现邮局关门了。The box is too small to hold all these things.那个盒子太小，装不下所有的东西。即时演练7单句语法填空(2016北京高考改编)To_make (make) it easier to get in touch with us, youd better keep this card at hand.(2015北京高考改编) To_catch (catch) the early flight，we ordered a taxi in advance and got up very

58、early. (2015福建高考改编) To_learn (learn) more about Chinese culture，Jack has decided to take Chinese folk music as an elective course. (2014陕西高考改编) To_work_(work)out the difficult maths problem, I have consulted Professor Russell several times.(2014四川高考改编)I hope to take the computer course.Good idea. To

59、_find_(find)out more about it, visit this website.(2014天津高考改编) Anxiously, she took the dress out of the package and tried it on, only to_find (find)it didnt fit.单句语法填空1They seemed to_be_writing (write) something for somebody now.2When to_hold (hold) the meeting is still to be discussed.3If you are t

60、he last student_to_leave (leave) the room, remember to_turn (turn)off the lights.4Mother had me go (go) to the shop and buy some salt.5To_prevent (prevent) the rising price affecting_(affect) the ordinary peoples life, the government will carry out a new policy.6George returned after the war, only t

61、o_be_told (tell) that his wife had left him. 7With so many things to_deal_(deal)with, I have to work late into the night.8(2013湖南高考改编) To_stay (stay) warm at night, I would fill the woodstove, then set my alarm clock for midnight so I could refill it.9He finds it hard to_focus(focus) his attention o

62、n one thing for longer than five minutes.10I hope_to_become (become) an astronaut some day.11The significant museum is said to have_been_built (build) about a hundred years ago.12Would you permit me to_smoke here?Sorry, we dont permit smoking_here in the reading room. (smoke).单句写作1(2016全国卷标准范文)This

63、is surely a_good_chance_for_more_people_to_see_them (对于更多人来说这是一个看到他们的好机会)2. (2015全国卷标准范文)Id_like_to_ask_you_to_write_an_article (我想让你写篇文章) for our schools English newspaper.3(2015四川高考满分作文)As a native speaker, I not only can speak Mandarin fluently, but also know_how_to_work_on_it_to_make_great_progr

64、ess (如何做来取得进步)4(2015四川高考满分作文)To_master (为了掌握) Mandarin, you should practice with native speakers as much as possible. Besides, you should_learn_to_think_(学会思考)like a Chinese. 5(2015浙江高考满分作文)In our everyday life, opinions vary from person to person, especially_when_a_class_activity_is_to_be_organized

65、 (特别是在组织班级活动时). 6(2015浙江高考满分作文)Once we were discussing_how_to_help_the_student (如何帮助这个学生) who was seriously ill in hospital.7(2015广东高考读写任务) At the graduation ceremony, just as she expected, she_was_very_proud_to_stand (她很自豪地站在那里) with a class of care, manners and confidence.8(2015广东高考读写任务满分作文)For one thing, it_not_only_helps_to_build_up_our_physical_health (它不仅能帮助我们强身健体), but helps us learn more effectively in turn.