高二英语寒假培优练习寒假作业04现在完成时与过去完成时（2份，原卷版+解析版）

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作业04 现在完成时和过去完成时
积累运用
现在完成时和过去完成时区别
注意：
1.现在完成时在since结构中使用时，since后面跟过去的时间或动作，主句用现在完成时。
例句：He has been ut f emplyment since he graduated frm the university.
自从他大学毕业以来，他一直失业。
The relatins between the tw cuntries have develped fr years since 2000.
自从2000年，这两个国家的关系已经发展了。
2. by与现在的时间搭配，用现在完成时；by与过去的时间搭配，用过去完成时。
例句：By nw he has cmpsed seven bks n his wn.
到现在为止，他已经独立创作了7本书。
By last year, we had mastered reading skills well.
到去年为止，我们已经很好得掌握了阅读技巧。
3. 过去完成时用于固定结构中：
（1） It was the first/secnd… time that …(that引导从句部分的谓语动词用过去完成时)。
例句：It was the third time that he had been laid ff.
这是第三次他被解雇。
（2）Hardly/Scarcely…when…和N sner…than…结构中，hardly, scarcely以及n sner后谓语动词用过去完成时，when，than后面用一般过去时。表示“一…就…”
例句：Hardly had he returned hme when he fund the huse brken int.
他一回家就发现房子被破门而入了。
（3）表示意向的动词，如hpe, expect, intend, mean, plan, think, suppse等使用过去完成时，并非表达过去的过去，而是表达对过去未曾实现动作的遗憾，表示“本…”。
例句：He had intended t decline the invitatin, but his friend persuaded him.
他本打算拒绝这个邀请，但是他朋友说服了他。
(4) 用于虚拟语气中，与过去事实相反的结构中。
与过去事实相反时，if引导的从句谓语动词用过去完成时had dne, 主句谓语动词用wuld/culd/shuld/might + have dne;
与过去事实相反时，wish后面引导的宾语从句中，谓语动词为had dne；as if引导的从句中，谓语动词用had dne。
例句：If he had fllwed my advice, he wuld nt have fallen behind thers.
如果他当初听我的建议，他就不会落后于别人了。
I wish she had
根据括号内所给的词，完成下面的句子。
1. Many parts f China (see) very heavy rainfall in the past few days.
【答案】have seen
【详解】考查现在完成时。句意：在过去的几天里 ，中国大部分地区有大降雨。in the past few days结构用于现在完成时，所以填have seen。
2. Instead f getting dwn t a new test as he (expect), he examined the previus wrk again.
【答案】had expected
【详解】考查过去完成时。句意：他没有着手于他期待的一个新任务，相反，他再一次检查了先前的工作。
根据句意，先“期待”，再“检查”，即动作expect发生于examine之前，因为examine用于过去时，所以填had examined。
3. The unemplyment rate in this district (fall) frm 6% t 5% since tw years ag.
【答案】has fallen
【详解】考查现在完成时。句意：自从两年前以来，这个地区的失业率已经从6%下降到5%。Since表示“自从”，后面接表示过去的时间或者谓语动词过去时，主句用现在完成时。所以填has fallen。
4. .It is the third time that yu (be) late this mnth.
【答案】have been
【详解】考查现在完成时。句意：这是这个月第三次你迟到。句式结构it is the +序数词+that后面用现在完成时；而it was the+序数词+that后面用过去完成时。因为此处是is，所以that后面用现在完成时，所以填have been。
5. They might have fund a better htel if they (drive) a few mre kilmeters.
【答案】had driven
【详解】考查虚拟语气结构中的过去完成时的使用。句意：如果他们开车多开几公里，他们可能就会找到一个比较好的酒店。If条件虚拟语气结构中，当与过去事实相反时，if引导的从句谓语动词用过去完成时，主句用wuld/culd/shuld/might+have dne，通过观察得知，主句谓语动词满足“与过去事实相反”的if虚拟语气结构，所以从句应该用过去完成时。所以填had driven。
6. .In the past decade, they ______________(realize) their gal, making the cmpany bring back t life.
【答案】have realized
【详解】考查现在完成时。句意：在过去的十年中，他们已经实现了他们的目标，使得公司起死回生。
此处in the past decade用于现在完成时结构，所以填have realized。
7. It was the furth time she (shp) nline fr hurs. I had already reminded her t think twice befre buying anything, but my wife ignred what I had said.
【答案】had shpped
【详解】考查过去完成时。句意：这是第四次我的妻子在网上购物好几个小时。我之前提醒过她买东西之前三思而后行，但是我的妻子不理会我说的话。It was the+序数词+that后面用过去完成时，所以填had shpped。
8. Over the past few mnths, I (learn) that n ne is perfect and that we all have flaws.
【答案】have learnt
【详解】考查现在完成时。句意：在过去的几个月中，我已经了解到没有人是完美的，我们所有人都有瑕疵。句中ver the past+段时间为时间状语，这个结构用于现在完成时，所以填have learnt。
9. If we (catch) the flight yesterday, we wuld be enjying ur hliday n the beach nw.
【答案】had caught
【详解】考查虚拟语气中过去完成时的使用。句意：如果我们赶上了昨天的航班，我们现在就能在沙滩上享受假日了。此句考查i条件句虚拟语气用法，当与过去事实相反时，从句用过去完成时，因为有yesterday,使用判断与过去事实相反，所以填had caught。
10. .I was sent t the village last mnth t see hw the develpment plan (carry) ut in the past tw years.
【答案】had been carried
【详解】考查过去完成时。句意：上个月我被送到那个村庄去看看这个发展计划在过去两年中的进展情况。
I was sent…发生在过去，即上个月，而计划的实施应该是被从被送去村庄之前算起的过去两年，所以此处应该表示过去的过去，又因为plan与carry ut是被动关系，所以填had been carried。
11. Hardly _______ she ________(g) t bed when the drbell rang.
【答案】had gne
【详解】考查过去完成时。句意：她一去睡觉，门铃就响了。此句中的结构为hardly…when…，表示“一…就…”hardly后面谓语动词用过去完成时，when后从句谓语动词用一般过去时，所以填had gne。
12. The bridge (build) by the end f last year.
【答案】had been built
【详解】考查过去完成时。句意：这座桥到去年年底已经被建好了。by与过去的时间连用，用过去完成时，所以填had been built。
13. Up t nw, he _______________(frm) the gd habit f ding exercise every mrning.
【答案】has frmed
【详解】考查现在完成时。句意：直到现在，他已经养成了每天早上锻炼身体的好习惯。up t nw表示“到目前为止”，用于现在完成时，所以填has frmed。
14. These days he _______________(cmplete) a majr task, s he is praised by his bss nw.
【答案】has cmpleted
【详解】考查现在完成时。句意：这些天他已经完成了一项重大的任务，所以他现在被他的老板表扬了。These days是现在完成时的标志性短语，所以填has cmpleted。
15. They____________(finish) their dinner by the time Sam jined them.
【答案】had finished
【详解】考查过去完成时。句意：到山姆加入他们的时候，他们已经吃完了他们的晚餐。by the time作为连词，连接的句子中谓语动词用一般过去时，主句应该用过去完成时。所以填had finished。
一、阅读理解
A
When the fifth grade schl year was almst ver, all the girls made autgraph (签名) bks. As I signed my classmates’ bks, I nticed their mms had written in them, t. “I culdn’t be pruder f yu. Can’t wait t see hw yu like junir high!” “Cngratulatins! We lve yu and knw yu have a bright future!”
I asked my mther t sign mine, t. When she handed it back t me, I was anxius t see what she had written. This is what I fund n the page:
When a thing is first begun,
Never leave it till it’s dne.
Be the labr great r small.
D it well r nt at all.
That was it? I was frzen. It was an indicatin t me that, if I culdn’t be perfect, I wasn’t gd enugh. I held back my tears, left the page in but secretly hped my classmates wuldn’t read it.
D it well r nt at all. Fr years, I battled perfectinism and never felt gd enugh fr mst f my life.
When my mther was in her eighties, I gave her a bk t fill ut s we culd knw mre abut her. It had questins at the tp f each page and then blank space t respnd. I secretly hped she’d been wrking n it all alng. Sadly, nt lng after, my mther passed away. When I srted ut her belngings, what I wanted mre than anything was that bk. What I fund stpped me shrt. On page ten, the questin was, “What’s the best advice yu gt frm yur parents?” Her respnse was what she had written in my autgraph bk. Even thugh I’d memrized it years ag, I read it at a slwer pace nw, seeing it in a new light.
It was written t her by her mther, and she was passing it dwn t her daughter in the same way. A gift frm her t me. She was giving me treasured, valuable advice when all I was thinking abut were wrds f praise. I understand it nw.
1．In paragraph 1, the authr fund that wrds frm ther classmates’ mms ________.
A．cntained reflectin n life B．expressed their thankfulness
C．shwed pride in their children D．featured a frmal writing style
2．Seeing her mm’s wrds n the autgraph bk, hw did the authr feel?
A．Disappinted.B．Mtivated.C．Hpeful.D．Anxius.
3．What des the underlined sentence in paragraph 5 imply?
A．The authr memrized the wrds frm her mm.
B．The authr was surprised t see the same wrds again.
C．The authr fund it easy t see the wrds clearly under the light.
D．The authr began t have a new understanding f her mm’s wrds.
4．What gift did the authr’s mm give her?
A．A visin f a perfect wrld. B．Encuragement t d things well.
C．Her mm’s wisdm f lving yurself. D．Her mm’s advice n living at a slw pace.
【答案】1．C 2．A 3．D 4．B
【导语】本文是一篇记叙文，主要讲的是作者起初对妈妈在签名簿上的写的内容不理解，在母亲去世后作者才理解了那些话的意义。
1．细节理解题。根据第一段“ I nticed their mms had written in them, t. “I culdn’t be pruder f yu. Can’t wait t see hw yu like junir high!” “Cngratulatins! We lve yu and knw yu have a bright future!”(我注意到他们的妈妈也在上面写了字。“我为你感到无比骄傲。等不及想看看你的初中生活了!”“恭喜你!我们爱你，知道你有一个光明的未来!”)”可知，在第一段中，作者发现其他同学妈妈的话是以他们的孩子为傲。故选C。
2．推理判断题。根据正文第三段“That was it? I was frzen. It was an indicatin t me that, if I culdn’t be perfect, I wasn’t gd enugh. I held back my tears, left the page in but secretly hped my classmates wuldn’t read it.(就这样？我僵住了。这对我来说是一种暗示，如果我不能做到完美，我就不够好。我强忍着眼泪，留下了那一页，但心里暗暗希望同学们不要看。)”可知，看到妈妈在签名簿上写的字，作者是失望的，故选A。
3．词句猜测题。根据倒数第二段“Even thugh I’d memrized it years ag, I read it at a slwer pace nw, seeing it in a new light.(尽管我多年前就已经记住了，但我现在读它的速度变慢了，以一种新的眼光看待它。)”和最后一段“I understand it nw.(我现在明白了。)”可知，第5段划线的句子表示作者开始对她妈妈的话有了新的理解。故选D。
4．推理判断题。根据作者妈妈写的话“When a thing is first begun, Never leave it till it’s dne. Be the labr great r small. D it well r nt at all.(当一件事刚开始时，不做完就不要离开。无论劳动是大是小。要么做好，要么不做。)”以及最后一段的“It was written t her by her mther, and she was passing it dwn t her daughter in the same way. A gift frm her t me.(这封信是她母亲写给她的，她正以同样的方式传给女儿。是她送给我的礼物。)”可知，作者的妈妈写的这些话就是给作者的礼物，从这些话可知，作者的妈妈鼓励作者把事情做好，故选B。
B
Mvies fr kids and teens aren’t nly designed t entertain. They can als include messages abut what’s right and wrng, what actins make a her r bad guy, and hw t deal with mral challenges. Cnsider The Hate U Give, a mvie that deals with hw teens can use their vice against racialized gun vilence. Or WALL-E, which cntains messages abut envirnmental destructin and cnsumerism.
But d children and teens want t watch mvies cntaining lessns abut mral behavir? Researchers at UCLA explred the questin in a recent reprt. They analyzed ver 1,700 mvies fr children and teens released in theaters after 2010 t see hw many character strengths were featured in each film. The quality and success f the films were measured in different ways: hw many stars each mvie received, hw much mney each mvie made in ticket sales during the pening weekend, and audience and film critic scres.
The results? Mvies that nticeably featured character strengths tended t make mre mney n the pening weekend bth within the United States and internatinally cmpared t mvies withut character strengths: This was true even when the researchers accunted fr hw many stars the film received, and the audience and critic scres, s their success wasn’t just abut being better-quality mvies.
Qualities like perseverance, curage, and teamwrk were featured mst ften (in ver 300 films each). But qualities like humility (谦逊) and integrity (正直) were less cmmnly highlighted (in fewer than 100 films each). “These are the character strengths that children struggle with the mst, and s creatrs may be missing an pprtunity t help children where they need it mst,” explain the researchers. The reprt als fund mvies made fr 13- t 18-year-lds had fewer character strengths cmpared t mvies fr yunger children.
“Teens are at a critical stage where they are easily influenced by their scial envirnments, including media,” explain the researchers. “There is a clear gap in the industry fr cntent directed at teens that prmtes psitive character strengths t help yuth s they can better deal with the key challenges and changes they are experiencing.”
5．What d The Hate U Give and WALL-E have in cmmn?
A．Bth intend t criticize racism.B．Bth are likely t develp values.
C．Bth fcus n envirnmental issues.D．Bth are mainly designed t entertain.
6．What did the reprt find abut the mvies featuring character strengths?
A．They received mre negative film reviews.B．They gt lwer audience and critic scres.
C．They gained impressive ticket sales.D．They were mainly targeted at verseas audience.
7．What can we learn abut the quality “integrity”?
A．It brught success t ver 300 films.B．It needs t be emphasized in mre films.
C．It is a character familiar t mst children.D．It was featured mre in films fr yunger children.
8．What is the best title fr the text?
A．Are Mvies with Mral Lessns Ppular?
B．Des the Film Industry Fail Its Yung Audience?
C．What Can Children Learn frm Watching Mvies?
D．Are Films fr Teens Different frm Films fr Yung Children?
【答案】5．B 6．C 7．B 8．A
【导语】本文是一篇说明文。文章主要说明了儿童和青少年看电影不仅仅是为了娱乐，它们还包括什么是对与错，怎样的行为可以造就英雄或产生坏人，以及如何应对道德挑战这样的信息。但是，儿童和青少年想看包含道德行为教育的电影吗？加州大学洛杉矶分校的研究人员在最近的一份报告中探讨了这个问题。
5．细节理解题。根据第一段“Cnsider The Hate U Give, a mvie that deals with hw teens can use their vice against racialized gun vilence. Or WALL-E, which cntains messages abut envirnmental destructin and cnsumerism.(想想《你给予的仇恨》吧，这部电影讲述了青少年如何用自己的声音反对种族化的枪支暴力。或者《机器人总动员》，它包含了环境破坏和消费主义的信息)”可知，《你给的仇恨》讲述了青少年如何用自己的声音反对种族化的枪支暴力，《机器人总动员》包含了环境破坏和消费主义的信息。因此，它们都很可能可以培养价值观。故选B。
6．细节理解题。根据第三段“Mvies that nticeably featured character strengths tended t make mre mney n the pening weekend bth within the United States and internatinally cmpared t mvies withut character strengths: This was true even when the researchers accunted fr hw many stars the film received, and the audience and critic scres, s their success wasn’t just abut being better-quality mvies.(与没有角色优势的电影相比，具有明显角色优势的电影往往在美国国内和国际上的首映周末都能赚到更多的钱：即使研究人员考虑了这部电影获得的明星数量、观众和评论家的评分，这也是正确的，所以它们的成功并不仅仅是因为电影质量更好)”可知，该报告发现了关于人物力量的电影获得了可观的票房收入。故选C。
7．细节理解题。根据第四段“But qualities like humility (谦逊) and integrity (正直) were less cmmnly highlighted (in fewer than 100 films each). “These are the character strengths that children struggle with the mst, and s creatrs may be missing an pprtunity t help children where they need it mst,” explain the researchers. The reprt als fund mvies made fr 13- t 18-year-lds had fewer character strengths cmpared t mvies fr yunger children.(但谦逊和正直这样的品质却不太常被强调（各自在不到100部电影中出现）。研究人员解释说：“这些都是孩子们最难以克服的性格优势，所以创作者可能会错过一个帮助孩子们最需要帮助的机会。”该报告还发现，为13至18岁的青少年拍摄的电影与为更年幼的儿童拍摄的电影相比，角色优势更少)”可知，“诚信”品质应该在更多电影中被强调。故选B。
8．主旨大意题。根据第二段“But d children and teens want t watch mvies cntaining lessns abut mral behavir? Researchers at UCLA explred the questin in a recent reprt. They analyzed ver 1,700 mvies fr children and teens released in theaters after 2010 t see hw many character strengths were featured in each film. The quality and success f the films were measured in different ways: hw many stars each mvie received, hw much mney each mvie made in ticket sales during the pening weekend, and audience and film critic scres.(但是，儿童和青少年想看包含道德行为教训的电影吗？加州大学洛杉矶分校的研究人员在最近的一份报告中探讨了这个问题。他们分析了2010年之后在影院上映的1700多部儿童和青少年电影，看看每部电影中有多少角色优势。电影的质量和成功是通过不同的方式来衡量的:每部电影获得了多少明星，每部电影在首映周末的票房收入，以及观众和影评人的评分)”结合文章主要说明了儿童和青少年看电影不仅仅是为了娱乐，它们还包括什么是对与错，怎样的行为可以造就英雄或产生坏人，以及如何应对道德挑战这样的信息。但是，儿童和青少年想看包含道德行为教育的电影吗？加州大学洛杉矶分校的研究人员在最近的一份报告中探讨了这个问题。故A选项“有道德教训的电影受欢迎吗”最符合文章标题。故选A。
二、完形填空
A wman and her dg walked thrugh the airprt, passing by dzens f peple. Suddenly the dg 9 withut making a sund, it sat like a statue and stared at a man carrying a suitcase.
The wman 10 the man carefully, waiting until he put dwn the suitcase. Then she shuted, “Plice. Dn’t make a mve!” Other 11 mved in. They quickly 12 the suitcase. The man had been carrying a bmb in it! On the TV news that evening, the 13 was a her. Thanks t this plice dg, smething terrible had been 14 . Lucky, the plice dg, had fund the bmb in a way n human ever culd. The dg had nt 15 r heard the dangerus device inside the suitcase. 16 , the animal had fund it with its 17 . Lucky had smelled the bmb.
A dg can sense drs (气味) that are thusands f times t 18 fr peple t smell. The part f a dg’s brain that deals with drs is much larger than that 19 part f the human brain. Peple depend n differences in 20 in rder t tell things apart. A dg n the ther hand, depends n differences in 21 .
Everything and everyne has an dr. That’s why highly trained dgs are ften used by the plice t 22 peple r find drugs. They have been taught t 23 specific smells. The animals’ sense f smell is s pwerful that they can even tell if a persn has recently tuched a certain bject.
Many f the different kinds f materials used in bmbs give ff exactly the same dr. A dg learns t search fr it. If the dg finds a bmb, hwever, it must never 24 it. It must nt let the persn wh is 25 the bmb knw. Instead, the dg has been trained t 26 . Plice fficers watch fr this 27 . Then, when the dg has finished 28 jb, plice can make their mve.
9．A．stppedB．diedC．jumpedD．attempted
10．A．refusedB．helpedC．watchedD．served
11．A．dgsB．carsC．animalsD．fficers
12．A．unpackedB．remvedC．tappedD．threw
13．A．wmanB．manC．animalD．fficer
14．A．warnedB．plannedC．cveredD．prevented
15．A．seenB．usedC．carvedD．bent
16．A．TherefreB．InsteadC．ThenD．Meanwhile
17．A．earsB．eyesC．tngueD．nse
18．A．farB．smallC．weakD．near
19．A．specialB．sameC．littleD．right
20．A．sundB．languageC．appearanceD．expressin
21．A．sizeB．tasteC．clurD．smell
22．A．fllwB．adptC．cnveyD．tease
23．A．cverB．recgnizeC．likeD．make
24．A．transfrmB．banC．shwD．spill
25．A．searchingB．clearingC．carryingD．delivering
26．A．sleepB．runC．changeD．sit
27．A．wrdB．gestureC．niseD．day
28．A．itsB．hisC．herD．their
【答案】
9．A 10．C 11．D 12．A 13．C 14．D 15．A 16．B 17．D 18．C 19．B 20．C 21．D 22．A 23．B 24．C 25．C 26．D 27．B 28．A
【导语】本文是一篇说明文，主要讲述了狗可以利用嗅觉来辨别东西，所以被训练用来帮助搜寻炸弹。
9．考查动词词义辨析。句意：突然，狗停了下来，没有发出任何声音，它像一尊雕像一样坐着，盯着一个提着手提箱的人。A. stpped停止，停下；B. died死；C. jumped跳；D. attempted努力；尝试。根据句中的“it sat like a statue”可知，狗一动不动地坐着，所以这里是说它停了下来。故选A。
10．考查动词词义辨析。句意：女人仔细地看着男人，一直等到他放下手提箱。A. refused拒绝；B. helped帮助；C. watched观看，观察；D. served服务。根据句中的“waiting until he put dwn the suitcase”可知，女人是仔细地看着男人，直到他放下手提箱。故选C。
11．考查名词词义辨析。句意：其他警官冲上前来。A. dgs狗；B. cars汽车；C. animals动物；D. fficers军官，警察。根据上文中的“Plice. Dn’t make a mve!(警察。别动！)”可知，这位女警察警告男人不要轻举妄动，接着其他警官冲上前来。故选D。
12．考查动词词义辨析。句意：他们迅速打开手提箱。A. unpacked打开（盒子﹑包﹑手提箱等）；B. remved去除；C. tapped轻拍；D. threw抛，扔。根据下文中的“The man had been carrying a bmb in it!(那个人一直在里面携带炸弹！)”可知，警察打开手提箱，发现里面有炸弹。故选A。
13．考查名词词义辨析。句意：在那天晚上的电视新闻中，这只动物成了英雄。A. wman女人；B. man男人；C. animal动物；D. fficer军官，警察。根据下文中的“Thanks t this plice dg”可知，这只警犬帮助搜查到了炸弹，成了英雄。故选C。
14．考查动词词义辨析。句意：多亏了这只警犬，才阻止了可怕的事情发生。A. warned警告；B. planned计划；C. cvered遮盖；D. prevented阻止。根据上文描写的狗帮助抓到携带炸弹行李箱的人和下文中的“the plice dg, had fund the bmb”可知，狗在炸弹爆炸前发现了炸弹，所以是阻止了可怕的事情发生。故选D。
15．考查动词词义辨析。句意：这只狗没有看到或听到手提箱里的危险装置。A. seen看见；B. used用；C. carved雕刻；D. bent弯曲。根据下文中的“Lucky had smelled the bmb.(Lucky闻到了炸弹的味道。)”可知，这只狗没有看到或听到手提箱里的危险装置，而是靠嗅觉找到的。故选A。
16．考查副词词义辨析。句意：相反，这只动物是用鼻子发现的。A. Therefre因此；B. Instead反而，却；C. Then然后；D. Meanwhile同时。上文“The dg had nt 15 r heard the dangerus device inside the suitcase.(这只狗没有看到或听到手提箱里的危险装置。)”说这只狗不是靠视觉或听觉找到炸弹的，“the animal had fund it with its ___17__. Lucky had smelled the bmb.”说它是用鼻子发现的，前后之间是替代转折的关系，应用Instead。故选B。
17．考查名词词义辨析。句意参考上题。A. ears耳朵；B. eyes眼睛；C. tngue舌头；D. nse鼻子。根据下文中的“Lucky had smelled the bmb.(Lucky闻到了炸弹的味道。)”可知，那只狗是用鼻子嗅到炸弹的。故选D。
18．考查形容词词义辨析。句意：狗能感觉到微弱数千倍的气味，而人们闻不到。A. far远的；B. small小的；C. weak微弱的；D. near差不多的。根据下文中的“The animals’ sense f smell is s pwerful”可知，狗的嗅觉非常强大，所以能够闻到非常微弱的味道，而这种味道对人类来说太过微弱而闻不到。故选C。
19．考查形容词词义辨析。句意：狗的大脑处理气味的部分比人类大脑的相同部分大得多。A. special特别的；B. same相同的；C. little小的；D. right正确的。根据句中的“The part f a dg’s brain that deals with drs is much larger than”和空后的“part f the human brain”可知，这里是对狗和人的大脑中处理气味的部分进行比较，这是相同的部分。故选B。
20．考查名词词义辨析。句意：人们根据外表的不同来区分事物。A. sund声音；B. language语言；C. appearance外观，外表；D. expressin表情。根据空后的“in rder t tell things apart”和上文中的“Lucky had smelled the bmb.(Lucky闻到了炸弹的味道。)”可知，狗靠嗅觉来区分事物，这和人不同，所以人是靠外表来区分事物的。故选C。
21．考查名词词义辨析。句意：另一方面，狗依靠不同的气味（来区分事物）。A. size尺寸；B. taste味道；C. clur颜色；D. smell气味。根据上文的“Lucky had smelled the bmb.(Lucky闻到了炸弹的味道。)”可知，狗依靠不同的气味来区别事物。故选D。
22．考查动词词义辨析。句意：这就是为什么警察经常用训练有素的狗来跟踪人或寻找毒品。A. fllw跟随；B. adpt收养，采用；C. cnvey表达，传递（思想、感情等）；D. tease戏弄。根据空后的“peple r find drugs”及常识可知，警察用警犬来跟踪人或寻找毒品。故选A。
23．考查动词词义辨析。句意：它们被教会识别特定的气味。A. cver覆盖；B. recgnize认出，认识；C. like喜欢；D. make制作。根据空后的“specific smells”和上文的“A dg n the ther hand, depends n differences in ___21___.(另一方面，狗依靠不同的气味。)”以及“That’s why highly trained dgs are ften used by the plice t 22 peple r find drugs.(这就是为什么警察经常用训练有素的狗来跟踪人或寻找毒品。)”可知，狗依靠气味来辨别东西，所以为了执行跟踪人或寻找毒品的任务，狗会被训练去识别特定的气味。故选B。
24．考查动词词义辨析。句意：然而，如果狗发现了一枚炸弹，它决不能表现出来。A. transfrm使改变形态；B. ban禁止；C. shw给……看，表现；D. spill（使）洒出。根据下文中的“It must nt let the persn wh is ___25____ the bmb knw.(它决不能让……炸弹的人知道。)”可知，如果狗发现了一枚炸弹，它决不能让携带炸弹的人知道，所以它不会表现出来。故选C。
25．考查动词词义辨析。句意：它绝对不能让携带炸弹的人知道。A. searching搜寻，搜索；B. clearing清除；C. carrying携带；D. delivering递送。根据上文中的“If the dg finds a bmb, hwever, it must never 16 it.(然而，如果狗发现了一枚炸弹，它决不能表现出来。)”可知，如果狗发现了炸弹，它不能表现出来，它不能让携带炸弹的人知道。故选C。
26．考查动词词义辨析。句意：相反，这只狗被训练坐下。A. sleep睡觉；B. run跑；C. change改变；D. sit坐。根据第一段中的“Suddenly the dg 9 withut making a sund, it sat like a statue and stared at a man carrying a suitcase.(突然，狗停了下来，没有发出任何声音，它像一尊雕像一样坐着，盯着一个提着手提箱的人。)”可知，狗发现炸弹时会坐下来。故选D。
27．考查名词词义辨析。句意：警察注意着这个姿势。A. wrd单词；B. gesture姿势；C. nise噪音；D. day一天。根据上文的“the dg has been trained t ___26___”可知，狗被训练在发现炸弹时坐下，而配合办案的警察就会注意着这个姿势。故选B。
28．考查代词词义辨析。句意：然后，当狗完成它的工作后，警察可以采取他们的行动。A. its它的；B. his他的；C. her她的；D. their他们的。根据空后的“jb”可知，这里指狗发现炸弹的工作，这是狗的工作。故选A。
拓展突破练
1. （2023年北京卷.语法填空）I turned up at the appinted hur fr a dinner, nly t find that n ther guest____________ (arrive) and my hstess was still in her sleeping suit.
【答案】had arrived
【详解】考查过去完成时。句意：我在约定的时间赴宴，结果发现没有其他客人到场，女主人还穿着睡衣。turn up用于一般过去时，“没有其他客人到场”应该发生在“我出现在约定的时间”之前，所以arrive应该用过去完成时，所以填had arrived。
2. （2023年北京卷.语法填空）Up t nw, China ___________(establish) a number f prtected areas with mangrves.
【答案】has established
【详解】考查现在完成时。句意：到目前为止，中国已经建立了一些红树林保护区。由up t nw可知，应该用现在完成时，所以填has established。
3. （2022年北京卷.语法填空）The use f thse plastics ____________ (increase) by 300% since 2019.
【答案】has increased
【详解】考查现在完成时。句意：自从2019年以来，那些塑料的使用已经增加了300%。Since表示“自从”，后面接过去的时间，句子应该用现在完成时。所以填has increased。
4. （2021年天津卷.单项选择）I wanted t make dumplings but fund I ____________(run ut f) flur, s I went ut t buy sme.
【答案】had run ut f
【详解】考查过去完成时。句意：我想做饺子，但是发现我已经把面粉用完了，所以我出去买了一些。
wanted，fund都是发生在过去，面粉用完应该是发现fund之前的动作，所以填had run ut f。
5. （2021年天津卷.单项选择）Mark is a genius. By the time he graduated, he ________ (ffer) jbs by a dzen cmputer cmpanies.
【答案】had been ffered
【详解】考查过去完成时。句意：马克是个天才。到他毕业的时候，他已经被很多电脑公司提供了工作的机会。ffer结构为ffer sb. sth.跟双宾语，此处表示“他被提供工作”，所以应该用被动态。又因为By the time为连词，连接句子谓语动词为一般过去时的时候，主句用过去完成时。所以填had been ffered。
6. （2021年天津卷.单项选择）Althugh a few have cme and gne, the restaurant's regular custmers __________(remain) the same fr nearly 40 years.
【答案】have remained
【详解】考查现在完成时。句意：虽然几个人来来往往，但是这家饭馆的常客一直以来40年间保持不变。
因为althugh引导的让步状语从句用现在完成时，表示到目前为止的状况，所以主句部分的时态保持一致，所以填have remained。
7. （2021年北京卷.语法填空）There ______ （be）a dramatic rise in the number f extreme weather events ver the past 20 years，caused largely by rising glbal temperatures，accrding t a new reprt frm the United Natins．
【答案】has been
【详解】考查现在完成时。句意：在过去的20年里，极端天气事件的数量急剧增加，这在很大程度上是由 全球气温上升造成的。根据时间状语ver the past 20 years, 此处为现在完成时的标志性短语，所以填has been。
8. (2021年全国新课标I.阅读理解B篇)Mr Tittertn is chairman f the Omega Ensemble but ___________(be) the grup’s fficial page turner fr the past fur years.
【答案】has been
【详解】考查现在完成时。句意：Tittertn先生目前是欧米茄合唱团的主席，并且在过去的4年中一直是这个团队的官方翻页人。fr the past fur years为现在完成时的标志性短语，所以此处用现在完成时。因为此处主语为第三人称单数，所以填has been。
9. (2020年天津卷.单项选择) The number f medical schls reached 18 in the early 1990s and ________ (remain) arund that level since.
【答案】has remained
【详解】考查现在完成时。句意：在20世纪90年代，医学校的数量达到了18所，并且自从那时开始，这个数量一直维持大概那个水平。since为关键的介词，指代since the early 1990s，所以句子的谓语动词用现在完成时。另外，句子的主语为the number f medical schls，谓语动词用单数。所以填has remained。
10. (2020年天津卷.单项选择) The student cmpleted this experiment t make cme true what Prfessr Jseph ___________(say).
【答案】had said
【详解】考查过去完成时。句意：这个学生完成了实验，实现约瑟夫教授所说的内容。这句话的谓语动词为cmpleted为一般过去时，而约瑟夫教授所说的话，应该发生在“cmpleted the experiment”之前，所以填had said。
现在完成时
过去完成时
形式
has/have +dne
had +dne
概念
过去某一时刻发生的动作持续到现在，并对现在造成影响
过去某一时刻已经开始并一直延续到这一时刻或在此时刻前已经完成的动作
标志性词
s far, until nw, up t nw, till nw, in/ver the last/past+段时间，these days…
by, by the time, befre, when