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高中英语名词性从句知识讲解以及练习题附答案一、名词性从句概述名词性从句是一种充当名词作用的从句，通常在主句中作主语、宾语、表语或同位语。
它通常由引导词（如that, whether, if, who, whom, whose, which, what等）引导，并且从句中含有一个主语和谓语。
名词性从句的种类有很多，包括主语从句、宾语从句、表语从句和同位语从句等。
下面我们将逐一介绍这些从句。
二、主语从句主语从句作为一个名词，通常位于句首，是一个句子，主要作用是作为主句的主语。
引导主语从句的词：What (什么)；Whether (是否)；If (是否)；That (那个)。
例句：What he said is true. (他说的是真的。
)Whether it will rain tomorrow is uncertain. (明天是否会下雨还不确定。
)If you go, I will go too. (如果你走，我也跟着走。
)That he is coming is good news. (他来的消息是好消息。
)注意：主语从句的谓语动词通常要用单数形式。
What引导的主语从句通常用来表示“事物”的概念。
三、宾语从句宾语从句是一个名词，通常位于主句的动词后面，作为主句的宾语。
它可以由常见的宾语从句引导词引导，例如whether, if, that, who, whom, whose, what, when, where, how等。
引导宾语从句的词：Whether (是否)；If (是否)；That (那个)；Who (谁)；Whom (谁)；Whose (谁的)；What (什么)；When (何时)；Where (何处)；How (如何)。
例句：I know that he is coming. (我知道他要来。
)I wonder if he is telling the truth. (我想知道他是否说了真话。
专题14 名词性从句——精讲深剖一．单句语法填空1.（2019全国卷I）While they are rare north of 88°,there is evidence they range all the way across the Arctic,and as far south as James Bay in Canada.【答案】that【解析】考查同位语从句。
根据句子结构分析可知，主句为there be句型，且结构完整，空格后为同位语从句，解释说明中心词evidence的内容，故填that。
2. （2018全国卷III）I'm not sure 61 is more frightened，me or the female gorilla (大猩猩) that suddenly appears out of nowhere.【答案】who【解析】考查宾语从句。
句意：我不确定谁受到了更大的惊吓，是我还是那只不知从何处突然出现的雌性大猩猩。
根据句意和句子结构可知，空处引导宾语从句，在从句中作主语，表示“谁”，故填who。
二．单项选择1.（2019江苏卷）Scientists have obtained more evidence ___________ plastic is finding its way into the human body.A. whatB. thatC. whichD. where【答案】B【解析】考查同位语从句。
句意：科学家已经获得更多证据，塑料正在进入人们的体内。
从句不缺句子成分，且与evidence指代的是同一事件，用that引导同位语从句。
故选B。
2.（2018江苏卷）By boat is the only way to get here, which is _______ we arrived.A. whereB. whenC. whyD. how【答案】D【解析】考查名词性从句。
语法复习之名词性从句名词性从句相当于名词，可分别作主句的主语、表语、宾语和同位语。
因此，名词性从句厅分为主语从句、表语从句、宾语从句和同位从句。
（一）引导名词性从句的连接词1、连接代词：who, whose, whom, what, which。
有词义，在从句中担任成分，如主语、表语、宾语、或定语等。
2、连接副词：when, where, why, how。
有词义，在从句中担任成分，作状语。
3、连接词：that, whether, if, as if。
that 无词义，在从句中不担任成分，有时可省略；if (whether), as if虽有词义，但在从句中不担任成分。
注意：连接代词与连接副词在句中不再是疑问句，因而从句中谓语不用疑问式。
连接代词与连接副词在从句充当句子成分，连接词whether 和if（是否），as if（好象）在从句中不充当句子成分，只起连接作用。
根据句义，如果连接代词与连接副词，whether、if 和as if都用不上时，才用that作连接词（that本身无任何含义）。
（二）主语从句1、主语从句在复合句作主语。
e.g. Who will go is not important.2、用it作形式主语，主语从句放在句末。
e.g. It doesn’t matter so much whether you will come or not.3、that引导主语从句时，不能省略。
e.g. That he suddenly fell ill last week made us surprised.（三）表语从句1、表语从句在复合句中作表语，位于系动词之后。
e.g. The question was who could go there.2、引导表语从句的连接词that有时可省去。
e.g. My idea is (that) we can get more comrades to help in the work.（四）宾语从句1、宾语从句在复合句中作宾语。
名词性从句包括主语从句、宾语从句、表语从句和同位语从句。
名词性从句是一种具有名词功能的非独立分句。
具体用法见下表：主语从句大多数主语从句都可以用it作形式主语而把主语从句置于句尾。
(what引导的主语从句表示“……的东西”时，一般不用it作形式主语；whatever, whoever, whichever一般也不用it作形式主语。
)►It makes no difference where we shall have the meeting.我们在哪开会无所谓。
【注意】(1)常见的it替代that引导的主语从句的句式主要有以下几种：①It＋系动词＋形容词(necessary/right/likely/important/certain...)＋that从句②It＋be＋名词(短语)(a pity/a shame/good news/a fact/an honour...)＋that从句③It＋be＋过去分词(said/told/heard/reported/decided/suggested...)＋that从句④It＋特殊动词(seem/appear/happen/matter)＋that从句(2)在“It is necessary/important/natural...＋that从句”的结构中，从句谓语常用“(should ＋)动词原形”。
宾语从句1．动词find, feel, think, consider, make, believe等后有that引导的宾语从句作宾语补足语时，则常用it作形式宾语而将that宾语从句后置。
►I think it necessary that we take plenty of boiled water every day.我认为每天摄入足量的白开水很有必要。
2．有些动词(短语)不能直接跟宾语从句，需要借助形式宾语it。
常见的有hate, enjoy, like, dislike, love, appreciate, see to等。
高考英语名词性从句知识点一、that 从句1、主语从句（1）that 从句作主语时，常用it 作形式主语，常见的句型有：It+be+形容词（obvious, true, natural, surprising, good, wonderful, funny, possible, likely, certain, probable, etc.）+ that从句It+be+名词词组（no wonder, an honor, a good thing, a pity, no surprise, etc.）+ that 从句It+be+过去分词（said, reported, thought, expected, decided, announced, arranged, etc.）+ that 从句（2）that可以省略，但 that 从句位于句首时，that不能省略。
2、宾语从句（1）常见的可以接 that 从句作宾语的动词有see, say, know, imagine, discover, believe, tell, show, think, consider, be sure, be afraid等。
在可以接复合宾语的动词之后，如 think, make, consider等，可以用 it 作形式宾语。
（2）That 从句一般不能充当介词宾语，偶尔可作except, in 的宾语。
3、表语从句（that不可省略）4、同位语从句连词that引导同位语从句时，应在某些抽象名词之后，如：fact, hope, desire, thought, suggestion, idea, news, problem, possibility 等，对前面的名词起补充说明的作用，that在从句中不担当任何成分，不能省略。
二、whether/if从句1、在表语从句和同位语从句中，只能用 whether 不能用 if；当主语从句放于句首时，只能用 whether 不用 if；当 it 作形式主语，主语从句放在句末时用 whether或if均可；discuss 后引导宾语从句时，必须用whether。
【最新整理，下载后即可编辑】名词性从句讲解在复合句中起名词作用的从句叫做名词性从句。
它包括主语从句、宾语从句、表语从句和同位语从句。
名词性从句是中学阶段的一个重要语法项目，在历年的高考中几乎都涉及到，并且每年的命题各有变化。
分析历届高考试题名词性从句考查的焦点主要有以下六个方面1. 考查名词性从句的语序问题2. 考查引导词that与what的区别3. 考查it在名词性从句中作形式主语或形式宾语的用法4. 考查whether与if的区别5. 考查名词性从句中的疑问词+ever引导的名词性从句与no matter+疑问词引导的状语从句的区别6. 考查名词性从句的虚拟语气问题语法要点剖析一、名词性从句主语从句、表语从句、宾语从句、同位语从句，在整个句子中所起的作用，相当于一个名词。
因此，这四种从句通称为名词性从句。
引导名词性从句的连接词可分为三类：连接词：that, whether, if （不充当从句的任何成分）连接代词：what, whatever, who, whoever, whom, whose, which.连接副词：when, where, how, why1. 主语从句作句子主语的从句叫主语从句。
主语从句通常由从属连词that，whether，if和连接代词what，who，which，whatever，whoever以及连接副词how，when，where，why等词引导。
that在句中无词义，只起连接作用；连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用，在从句中充当从句的成分。
例如：What he wants to tell us is not clear. 他要跟我们说什么，还不清楚。
It is known to us how he became a writer. 我们都知道他是如何成为一名作家的。
Where the English evening will be held has not yet been announced.英语晚会将在哪里举行，还没有宣布。
高中英语名词性从句详细讲解与练习在句子中起名词作用的从句叫名词性从句。
名词性从句的功能相当于名词词组，它在复合句中能担任主语、宾语、表语、同位语，因此根据它在句中不同的语法功能，名词性从句又可分为主语从句、宾语从句、表语从句、同位语从句。
引导名词性从句的词叫做连接词，包括：1.连词（在名词性从句中只起连接作用，不作成分）2.连接代词（在名词性从句中作主语、宾语或表语）3.连接副词（在名词性从句中作状语）所有的名词性从句的语序都是陈述语序。
I主语从句：是在主句中作主语的从句。
它由连接词引导，通常位于谓语动词之前。
连接词：1.连词：在从句中不充当任何成分，常见的引导主语从句的连词有that, whether oThat he got the first prize excited him much.他获得一等奖一事使他非常兴奋。
It is doubtful whether we can get there on time.我们能否按时到达那儿还不确定。
D that引导的主语从句:在从句中不作任何成分，也没有实际意义。
一般情况下that不可省略。
That light travels in straight lines is known to all.众所周知，光沿直线传播。
That you don't like him is none of my business.你不喜欢他不关我的事。
2）whether引导的土语从句:常置于句首，表示“是否”之意；if一般不引导主语从句。
Whether he can finish his task on time is of greatimportance.他是否能按时完成任务非常重要。
Whether you can succeed or not depends on howhard you work at it.你能否成功取决于你努力的程度。
2.连接代词：在从句中起名词或代词的作用，常作从句的主语、宾语、表语或定语,有具体意义且不能省略。
v1.0 可编辑可修改1高考英语名词性从句讲解【考情剖析】名词性从句是历年高考的重点和难点也是热点。
名词性从句相当于名词，可用作主句的主语、表语、宾语和同位语。
因此，名词性从句分为主语从句、表语从句、宾语从句和同位从句。
引导名词性从句的衔接词有：衔接代词：who, whose, whom, what, which ，有词义，在从句中担任成分，如主语、表语、宾语、或定语等；衔接副词：when, where, why, how ，有词义，在从句中担任成分，作状语；衔接词：that, whether, if, as if ，if (whether), as if 虽有词义，但在从句中不担任成分；that 无词义，在从句中不担任成分，有时可省略。
今后对名词性从句的考查仍将集中在关联词的选用上，特别石堆what 引导的名词性从句的考查。
名词性从句与其他从句的混合考查将在今后高考中占据一席之地。
易混句型的辨析，比如it 作方式主语，主语从句后置的句型与强调句型的辨析将仍作为高考考查的重点。
【知识点归纳】名词性从句的用法在句子中起名词作用的句子叫名词从句 (Noun Clauses ）。
名词从句的功用相当于名词词组, 它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不一样的语法功用，名词从句又可区分称为主语从句、宾语从句、表语从句和同位语从句。
一、引导名词性从句的衔接词引导名词性从句的衔接词可分为三类：连词：that （无任何词意）；whether, if （均表示“能不能”标明从句内容的不确定性）；as if ,as though （均表示“似乎”，“似乎”）。
以上在从句中均不充任任何成分衔接代词：what, whatever, who, whoever, whom, whose, which. Whichever, whomever 衔接副词：when, where, how, why 不可省略的连词： 1. 介词后的连词2. 引导主语从句和同位语从句的连词不可省略。
2023-2024学年高考英语专项真题试卷练习——名词性从句1.（广东省广东省四校联考2023-2024学年高三试题）The study doesn’t note these plant-based alternatives carry similar health risks or not.2.（广东省佛山市南海区2023-2024学年高三测试题）It has rich cultural tourism resources as it is ___ Mount Tai rises, the Yellow River flows into the sea, and Confucius was born.3.（2024届浙江省强基联盟适应性考试试题）In my case this is happened—my parents turned in to me and my needs and the shyness all but disappeared completely over time.4.（湖南省岳阳第一中学2023-2024学年高三开学试题）Today the future of Dafen may depend onit is able to earn respect of the art world.5.（湖南省常德市第一中学2023-2024学年高三试题）Huawei withstood strict sanctions from the US govt. and now able to produce their own 5G phones, a great victory! does not kill you will make you stronger!6.（湖南省衡阳市衡阳县2023-2024年高三试题）Cobb, for her party, started to ask conference organizers who invited her to speak she could do so remotely; about three-quarters of the time, they agreed.7.（湖南省湖南师范大学附属中学2023-2024学年高三试题）Catching sight of the sunrise and sunset, Kua Fu suddenly hit upon an idea he wanted to race against the sun to see who ran faster!8.（湖南省益阳市南县第一中学2023-2024学年高三试题）For example, Mary-Jo Saunders is learning a Chinese poem today. is special is that she is able to recite it without an accent.9.（湖南天壹名校联盟2023-2024学年高三大联考试题）She noted that cultural integration has always been a proposition (主张) of the Maltese government, and_____ cooperation between the two sides should be based on equality and mutual benefit in order to be sustainable.10.（湖北省孝感市重点高中协作体2023-2024学年高三试题）Meanwhile, fans disagree on often one should wear the clothing, every day or on special occasions like festivals and weddings.11.（湖北省腾云联盟2023-2024年高三联考试题）Phrases like “replace weapons of war with gifts of jade and silk” and “gentle as jade” perfectly show jade symbolizes in the minds of Chinese people.12.（湖北省宜荆荆恩2023-2024学年高三起点试题）Its unique taste of freshness, sourness, hotness and spiciness is modern people and young people prefer.13.（江苏省镇江第一中学2023-2024学年高三学情检测）Discoveries made during the latest excavation of Pit No.1 at the Mausoleum of Qin Shi Huang, China’s first emperor, have allowed Chinese archaeologists to gain more insight into the world-famous Terracotta Warriors and their weapons were made.14.（江苏省2023-2024学年高三学情调研试题）We should trust life and trust our own abilities to understand_____ is right and wrong, what decision to make and how to solve problems.15.（江苏省百校联考2023-2024学年高三试题）“It proves to me the cause I’ve engaged in is world-class and for all humanity,” Chen said.16.（江苏省常州市联盟校2023-2024学年高三10月调研试题）There is no consensus on to do about “the large language models that are trained on copyrighted works.”17.（江苏省常州市十校2023年高三联合调研）Therefore our findings raise an exciting possibility ___ we may be able to promote health and happiness by developing positive attitudes such as optimism.”18.（江苏省东台中学2023-2024学年高三10月试题）Its unique taste of freshness, sourness, hotness and spiciness is modern people and young people prefer.19.（江苏省南京市第九中学2023-2024学年高三质量调研）bothers many children is that their parents aren’t fully aware of the importance of their privacy.20.（江苏省南京市五校2023年高三联考试题）But after assessing the number of extant pandas in the late 1970s, China came to realize the fact the animals had become a rare and endangered species. 21.（江苏省苏州中学校2023-2024学年高三试题)This was typically Huang Quande, fisherman-turned-photo model, looked in his photos with tourists from China and abroad.22.（江苏省苏州中学校2023-2024学年高三试题）Many love to find out the pictures were originally taken.23.（河北省部分重点高中2023-2024学年高三综测试题）excites the organizing committee is that the Peony Pavilion has attracted a growing young audience since its premiere in Beijing.24.（河北省石家庄市2023-2024学年石家庄市一中高三试题）On the first day of the Start of Autumn, usually people will weigh themselves and compare their weight to it was at the Start of Summer.25.（河北省唐山市2023-2024学年高三演练试题）Despite the fact a skywell’s size anddesign vary from region to region, it is almost always rectangular (长方形) and located in the core of a house.26.（2024届福建省三明市等5地高三一模试题）These words of her give us a look into the heart of this amazing woman, and carried her through a life of hard choices.27.（2024届辽宁省沈阳市浑南区东北育才学校一模试题）they discover instead is a work of art with a museum inside. Meier took some basic materials metal, stone and glass.28.（2024届辽宁省本溪市高中高三一模试题）The fresh thin air, snow-covered mountains and graceful animals running on the plains are we’re here-to observe Tibetan antelopes, which are being hunted, legally, for their valuable fur.29.（2023·内蒙古赤峰·高三赤峰二中校考阶段练习）The father and his son got lost in the mountain and they had to eat food they could find there.30.（2023·黑龙江哈尔滨·高三哈尔滨三中校考）When her daughter came back from Australia, she found her quite different from she was 3 years ago.二单项选择1．________ he lied about his academic background at the interview really surprised us after the truth came out.A．That B．What C．Whether D．When2．While they are rare north of 88°, there is evidence _______ they range all the way across the Arctic, and as far south as James Bay in Canada.A．that B．in which C．where D．from which3．The two men from the truck were poorly dressed and spoke in ________ sounded like an eastern European language.A．which B．that C．what D．where4．Among the many unsolved mysteries about dinosaurs, ________ really interests me is their disappearance.A．that B．which C．whether D．what5．Sometimes advertisements make it possible for companies to sell the customer money cannot buy.A．what B．which C．that D．whether6．In our daily life, it is a piece of cake to find that the same boiling water softens the potato and hardens the egg. Hence, it’s about ________ you’re made of, not the circumstances.A．that B．what C．how D．who7．The place the bridge is supposed to be built should be the cross-river traffic is the heaviest.A．which, that B．at which,whereC．at which,that D．where, in which8．work and creative activities have been important drivers of human progress is deeply rooted in our social values.A．How B．Whether C．That D．Which9．I promise to make you all proud again in direction life may take me.A．however B．wherever C．whenever D．whatever10．All of my classmates are hopeful about________2022 will bring not only in our studies but also in our overall development.A．how B．which C．that D．what11．A warm thought came to me ____ I might help wash my mom’s feet on Thanksgiving Day.A．if B．when C．which D．that12．There are some differences between American and British English, but do you know the differences came into being?A．how B．what C．whether D．that13．What the doctors really doubt is ________ the patient will recover from the serious disease soon.A．whenever B．if C．whether D．that14．________ remains important is that we have an incredible desire to think and create, and that’s the real spirit of invention.A．It B．That C．What D．As15．Mental health involves________ you process things such as stress and anxiety.A．how B．what C．why D．which16．______ could be judged from her eyes that she was terribly sorry for ______ he had done.A．As; what B．It; what C．What; that D．That; that17．Without his support, we wouldn’t be ________ we are now.A．how B．when C．where D．why18．________ is highly recommended is cheongsam, ________ traditional women costume featuring strong national flavor.A．That; 不填B．What; 不填C．That; which D．What; which19．—Do you doubt he has passed the examination?—I don’t doubt at all he has passed all the examinations.A．that; whether B．that; thatC．whether; that D．whether; whether20．The reason________ she didn’t get the job was________ her English was not very good.A．which; that B．why; thatC．why; because D．that; because21．I was wondering__________to go upstairs or follow Marxim to the library.A．where B．whenC．whether D．how22．We have come to the conclusion ________ the company has been making great progress these months.A．which B．that C．as D．what23．________ you should do is to get down to your study from now on. Please concentrate on ________ is of great importance to your future development.A．What; what B．That; whereC．What; where D．That; that24．I hope to set up our company in will be a promising land, a place is full of opportunities.A．where, where B．where, that C．what, where D．what, that25．________ is known to all is that the outstanding academic atmosphere, as well as various festivals and sports, draws many students to our school.A．It B．Which C．What D．As26．People of Shennongjia living and working in harmony with nature highlights _____ understanding, awareness and hardwork have contributed towards protecting natural world.A．how B．when C．why D．what27．I had dreamed of this moment many times in my childhood. But when you finally make it it’s totally different from ________ you had imaginedA．when B．what C．that D．which28．We’ve done a solid preparation so this is ________ our team is supposed to shine.A．what B．whether C．which D．where29．The Palace Museum is ________ the royal families used to live and it’s now a historical museum with collections of valuable antiques.A．what B．which C．where D．how30．Betty raised the important question of________will be in charge when the manager was away on business.A．whoever B．whom C．whomever D．who三语篇填空Passage 1阅读下面材料，在空白处填入适当的内容(1个单词)或括号内单词的正确形式。
专题14 名词性从句——高效演练一．单句语法填空1．________ she was invited to the ball made her very happy．【答案】That【解析】空格处引导主语从句。
从句中不缺少成分，并且句意完整，因此用that引导该主语从句。
2．Children should be reminded of ________ they should do in public places．【答案】what【解析】句意：应该提醒孩子们在公共场所应该做些什么。
所填词引导宾语从句且在从句中作do的宾语，意为“……的事情”，且what引导介词of后的宾语从句。
故用what。
3．Dick enjoys painting but he knows the fact ________ he doesn't have what it takes to be a professional．【答案】that【解析】句意：迪克喜欢画画，但他知道自己没有成为一名专业画家所需要的(素质)。
that引导同位语从句，说明fact的具体内容。
4．Success partially depends on ________ you have the patience to do simple things perfectly．【答案】whether【解析】根据句子结构可知，设空处引导宾语从句；根据句意可判断，设空处意为“是否”，其前有介词on，故填 whether。
5．I lost my cell phone yesterday． Can you tell me ________ I can buy one?【答案】where【解析】where引导宾语从句，且在从句中作地点状语。
6．It never occurred to me ________ you could succeed in persuading him to change his mind．【答案】that【解析】it为形式主语，真正的主语为后面的从句，从句中不缺少成分，且句意完整，因此用that。
7．________ breaks the law will be punished．【答案】Whoever【解析】句意：无论谁违法都将受到惩罚。
主语从句中缺少主语，指人，并且表泛指，故用whoever。
8．She will give ________ needs help a warm support．【答案】whoever【解析】句意：凡是需要帮助的人，她都会给予热情的支持。
由句意可知，应填whoever，在宾语从句中充当主语。
9．I have no idea ________ the girl is doing in her room now．【答案】what【解析】句意：我不知道那个女孩现在在房间里干什么。
由句意可知，应填what，在同位语从句中作宾语，且意为“……的事情”。
10．________ is well known to everyone, I should say, is that a man becomes learned by asking questions．【答案】what【解析】分析句子成分可知，主语从句中缺少主语，且指事物，因此用what。
11．Exactly ________ the potato was introduced into Europe is uncertain, but it was probably around 1565．【答案】when【解析】句意：土豆被引入欧洲的确切时间不能确定，但很可能是1565年左右。
分析句子结构可知，设空处为主语从句的引导词，从around 1565判断，这里指时间，故填when。
12．It shocked the world ________ the United States withdrew from some major agreements it had been committed to, including the 2015 Paris Agreement on climate change and the 2015 Iran Nuclear Deal．【答案】that【解析】句意：令世界震惊的是，美国退出了它所承诺的一些主要协议，包括2015年《巴黎气候变化协定》和2015年《伊朗核协议》。
此处it是形式主语，真正的主语是that引导的主语从句。
13．I need help now! I have to fix a leaking pipe in my bathroom but I'm not sure ________ to begin．【答案】where【解析】句意：我现在需要帮助！我不得不修理洗手间里一个正在漏水的管子，但是我不确定从何处着手。
此处表示是管子哪里漏水，表示地点，填where。
14．Forty grams of meat per day is ________ people should consume in order to stay fit．【答案】what【解析】句意：为了保持健康，人们每天应该消耗40克肉。
“________ people should consume”是表语从句，该从句中，consume缺少宾语，且表示“所……的东西”，故要用what引导该从句。
15．The famous player tried again and again after each failure． That's ________ he succeeded at last．【答案】why【解析】句意：每次失败后，这位著名的球员一次又一次地尝试。
那就是为什么他最终成功了(的原因)。
be后面的是一个表语从句，用why引导从句，表示结果，故填why。
16．The retired engineer is showing ________ the wheelchair climbs stairs, which all the curious visitors want to know．【答案】how【解析】句意：这位退休的工程师正在展示轮椅如何爬楼梯，这是所有有好奇心的游客想知道的。
由句意可知，填how，意为“怎么，如何”。
这是how引导的宾语从句。
17．It hasn't been made clear ________ the new underground line is to be open to traffic．【答案】when【解析】句意：新的地铁线路何时开放还不清楚。
由句意可知，填when。
这是when引导的主语从句，it是形式主语。
18．The problem is ________ sometimes when we are given something on a constant basis, we start to take it for granted and forget to be thankful for what we already have．【答案】that【解析】句意：问题是，有时候当我们不断地被给予某些东西时，我们就认为这是理所当然的，从而忘记了要对我们已经拥有的东西应该心存感恩。
由于从句中成分完整，因此应用that来引导，that在从句中只起连接作用，不作任何成分。
19．Ten percent of life is ________ happens to you and ninety percent is ________ you respond to it．【答案】what; how【解析】句意：生活的百分之十是事件本身，另有百分之九十在于你如何回应它。
分析句子结构可知，第一空引导表语从句，happens to you缺少主语，意为“什么事”，因此应用what来引导；第二空也引导表语从句，you respond to it成分齐全，因此应用how，表方式。
20．After a day's exhausting climb we arrived at ________ we had been told was Garden in the Air．【答案】what【解析】句意：经过一天筋疲力尽的攀爬，我们终于到了那个被称为“空中花园”的地方。
分析句子结构可知，at为介词，后面是一个宾语从句，we had been told为插入语，宾语从句中缺主语，且在句中意为“……的事物(东西)”，故用what。
21．Sometimes, ________ we show our gratitude to a person is reflected in the kind of food we serve him or her．【答案】how【解析】句意：有时我们如何表达对一个人的感激之情会体现在招待他或她的食物种类上。
此处用how，表方式，引导主语从句。
22．It remains to be seen ________ this plan is practical enough to keep the project going．【答案】whether【解析】句意：这个计划是否足够可行来让这个工程继续下去，还有待于进一步观察。
whether引导主语从句，it是形式主语。
23．Some summer camps can provide you with as many as ten courses, and you are required to choose ________ suits you best．【答案】whichever【解析】句意：一些夏令营可以提供多达10门课程，你可以从中选择最适合自己的课程。
choose后面是宾语从句，从句中缺少主语，且前句提到范围即as many as ten courses，故此处表示你最喜欢的任何一门，故填whichever。
24．It is reported that a huge percentage of bird species are in danger． It's ________ their habitats or homelands are disappearing．【答案】because【解析】句意：据报道大部分鸟类正面临危险。
这是因为它们的栖息地或家园正在消失。
空格处引导表语从句。
根据前后两句的关系，空格处表示因果关系，故使用because。
25．I just wonder ________ it is that all the villagers think highly of him．【答案】why【解析】句意：我就是想知道为什么所有的村民对他的评价这么高。
