题目内容
15.It's hard to imagine how a single-celled blob (单细胞斑点)in the ocean evolved into a fish*a turtle,or eventually a human.2.5billion years ago,lives on Earth were all single-celled.Then,these tiny creatures started getting bigger,evolving into multi-celled blobs that eventually became animals.Multicellularity is one of the most important steps in evolution,but it's hard to study because tiny blobs in the ocean don't really leave fossils behind.However,there're plenty of single-celled creatures still living today.And one of them,the choanoflagellate (领鞭毛虫),seems to be our closest living smgle-celled cousin.This means that,long time ago,a common ancestor of both you and the choanoflagellate evolved in two different directions.By looking at what choanonagelates and animals have m common,scientists can start to describe that single-celled common ancestor."Choanoflagellates are really a unique Window back in time to the origin of ammals and humans."said Dan Rokhsar of the University of California.
Looking at a choanoflagellate,it's impossible to see any resemblance to an animal.It seems by moving a long tail.The tail has tentacles that catch bacteria to eat.But inside that single cell in the genes,Dan Rokhsar and his team found something interesting.Choanoflagellates genes produce cadherin proteins (钙粘蛋白),which have a well-known role in animals:they slick cells together like glue.But a choanoflagellate only has one cell!Scientist Nicole King thought that the choanoflagellaes used this glue to hold themselves to the surlace of water.Fhe leap to multicellularity then makes more sense,because the first multi-ceiled creatures were able to put this glue to a new and different purpose-holding their cells together!Now that's a clever trick of evolution.
32.Which of the following statements is true according to the passage?C
A.Multi-celled blobs didn^exist on the earth until 1billion years ago.
B.Choanoflagelates and animals share nothing in common.
C.Choanoflagellates and human beings share the same ancestors.
D.By watching the movement of a choanoflagellate,scientists have found that it resembles an aniinaL
33.What is the passage mainly about?D
A.The function of a single-ce]led blob.
B.The features of multicellularity.
C.The result of scientists'study on the multicelled blobs.
D.The evolution of single-celled blobs.
34.Why is it difficult for scientists to study the process of multicellularity?B
A.Because it happened billions of years ago.
B.Because they couldn't find any fossils in the ocean.
C.Because no singie-celiecl blobs have been left for them.
D.Because both humans and animals evolved from single-celled blobs.
35.Cadherin protein from choanoflagellates'genes are probably used toA.
A.stick them to the surface of water
B.produce their own ceils
C.hold their cells together
D.swim with a long tail.
分析 本文属于说明文阅读,作者通过这篇文章主要向我们描述了单细胞斑点的进化的有关信息和例子.
解答 32.C.细节理解题.根据第二段This means that,long time ago,a common ancestor of both you and the choanoflagellate evolved in two different directions可知领鞭毛虫和人类有共同的祖先;故选C.
33.D.推理判断题.根据第一段It's hard to imagine how a single-celled blob (单细胞斑点)in the ocean evolved into a fish*a turtle,or eventually a human.2.5billion years ago,lives on Earth were all single-celled.Then,these tiny creatures started getting bigger,evolving into multi-celled blobs that eventually became animals可知文章主要讲单细胞斑点的进化;故选D.
34.B.细节理解题.根据第一段Multicellularity is one of the most important steps in evolution,but it's hard to study because tiny blobs in the ocean don't really leave fossils behind可知科学家研究多细胞生物的过程难是因为他们在海里找不到任何化石;故选B
35.A 细节理解题,根据文章Scientist Nicole King thought that the choanoflagellaes used this glue to hold themselves to the surlace of water可知领鞭毛虫的钙粘蛋白用于维持身体表面的水;故选A
点评 考察学生的细节理解和推理判断能力,做细节理解题时一定要找到文章中的原句,和题干进行比较,再做出正确的选择.在做推理判断题不要以个人的主观想象代替文章的事实,要根据文章事实进行合乎逻辑的推理判断.
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A. | promises | B. | benefits | C. | puzzles | D. | satisfies |
Fourteen-year-old Kimberly Mays (40)Cneither description,but her recent court victory could (41)Bhelp children who do.Kimberly has been the (42)Bof an angry custody battle between the man who raised her and her biological parents,with whom she has never lived.A Florida judge (43)Athat the teenager can remain with the only father she's ever known and that her biological parents have"no legal (44)D"on her.
Shortly after (45)Ain December 1978,Kimberly Mays and another baby were mistakenly switched and sent home with the (46)Dparents.Kimberly's biological parents,Ernest and Regina Twigg,received a child who died of a heart disease in 1988.Medical tests (47)Dthat the child wasn't the Twiggs'own daughter,but Kim only was,thus leading to a custody (48)Awith Robert Mays.In 1989,the two families (49)Cthat Mr.Mays would maintain custody with the Twiggs getting (50)Crights.Those rights were ended when Mr.Mays decided that Kimberly was being (36)A.
The decision to (52)BKimberly with Mr.Mays caused heated discussion.But the judge made clear that Kimberly did have the right to sue (起诉) (53)Cher own behalf.Thus he made it clear that she was (54)Ajust a personal possession of her parents.Biological parentage does not mean an absolute ownership that cancels(取消) all the (55)Cof children.
36.A.terrible | B.sad | C.true | D.natural |
37.A.but | B.if | C.when | D.because |
38.A.settle | B.live | C.suffer | D.gather |
39.A.have | B.refuse | C.stick | D.fail |
40.A.likes | B.gives | C.fits | D.knows |
41.A.actually | B.eventually | C.successfully | D.abruptly |
42.A.victim | B.object | C.sacrifice | D.teenager |
43.A.ruled | B.believed | C.ordered | D.indicated |
44.A.expectation | B.action | C.effect | D.claim |
45.A.birth | B.judgment | C.operation | D.school |
46.A.biological | B.own | C.kind | D.wrong |
47.A.examined | B.explained | C.decided | D.showed |
48.A.battle | B.right | C.agreement | D.decision |
49.A.thought | B.quarreled | C.agreed | D.prepared |
50.A.equal | B.same | C.visiting | D.speaking |
51.A.harmed | B.forbidden | C.wounded | D.hidden |
52.A.make | B.leave | C.give | D.keep |
53.A.by | B.through | C.on | D.in |
54.A.more than | B.no more than | C.not more than | D.less than |
55.A.freedom | B.happiness | C.rights | D.ideas |
Since all the(37)B were taken,I stood.Suddenly,I felt someone pulling on my bag.(38)B I probably was in someone's way,I moved over slightly.But in one quick motion(动作),I felt my bag removed from my back,and in a flash it was(39)D.I turned around to see who the thief was.I looked at the people standing behind me,but didn't see my bag or anyone(40)A.My heart sank and I began to(41)A.
I glanced around the car only to find directly across from me was an elderly lady,and sitting on her lap was my(42)B.I tried to get it back from her lap.But as I began to(43)A it up,she quickly grabbed(抓住) it back and held onto it.I looked around at the people standing beside me,and those sitting beside her,but no one took any(44)C of the situation.Trying not to cause a(an)(45)B,I tried to negotiate through gestures.I used my hands as best as I could,but she(46)D my requests for my bag and pointed to my back.She picked up my bag,showing how(47)C it was.I finally began to understand.She was holding my bag to(48)C me.
At the next stop,a middle-aged woman got on the crowded subway.Another elderly woman sitting down took her bag,(49)D it on her lap.They didn't talk;(50)A this older woman was more than pleased to sit with this stranger's bag on her lap throughout her journey.
As the subway pulled into the main downtown station and I was getting ready to get off,the woman(51)D handed me back my bag.But(52)C I had a chance to thank her,she had disappeared into the crowd.
Sadly,this considerate custom was more (53)B to me than if I had been robbed.Everyone back home had heard of being robbed-that was (54)A city behavior-but having a stranger hold onto someone's bag out of (55)C,in a city of twelve million people-that was truly unusual.
36.A.loss | B.aim | C.cause | D.difference |
37.A.cars | B.seats | C.buses | D.stations |
38.A.Deciding | B.Assuming | C.Admitting | D.Expecting |
39.A.broken | B.emptied | C.opened | D.gone |
40.A.suspicious | B.nervous | C.cautious | D.dangerous |
41.A.panic | B.scream | C.leave | D.regret |
42.A.book | B.bag | C.money | D.map |
43.A.pull | B.bring | C.check | D.wrap |
44.A.advantage | B.charge | C.notice | D.photo |
45.A.attack | B.scene | C.accident | D.change |
46.A.received | B.handled | C.considered | D.ignored |
47.A.small | B.useful | C.heavy | D.special |
48.A.remind | B.tease | C.help | D.warn |
49.A.dropping | B.tapping | C.closing | D.setting |
50.A.yet | B.so | C.or | D.because |
51.A.angrily | B.gratefully | C.anxiously | D.gently |
52.A.until | B.once | C.before | D.while |
53.A.amusing | B.surprising | C.annoying | D.disappointing |
54.A.usual | B.harmful | C.practical | D.suitable |
55.A.curiosity | B.pity | C.kindness | D.desperation |