1、Unit 1 Nature in the balance课时分层作业(一).单词拼写1Were going to spend a weekend on the South American continent(大陆).2Her old man left her a few million (百万)when he died.3This region is the home of many species (物种)of wild flower.4This area of France has a pleasing climate (气候)in August.5Hundreds of tree sp
2、ecies is facing extinction(绝种).6He may say no，but theres no harm(伤害)in asking.7The cost of living(生活)has risen sharply.8Her nervousness quickly disappeared(消失)once she was on stage.9The development of the food industry depends on that of agriculture(农业).10The impact (冲击)of the blow knocked Jack off
3、balance.阅读理解ABig cats have existed on the earth for millions of years，though scientists arent sure exactly how long.But a new study indicates that a skull(颅骨)of a snow leopard(豹)relative that was recently unearthed is 4.4 million years old.That makes it the oldest big cat fossil(化石)ever found.A team
4、 of US and Chinese scientists unearthed the skull in Tibet.This creature is not a direct ancestor to big cats，but it is closely related to the snow leopard，the study leader Jack Tseng told the Associated Press.The fossil lends evidence to the belief that big cats existed in Asia and spread out from
5、there.Big cats are at the top of the food chain and have few predators of their own.Big cats include snow leopards，clouded leopards，tigers and lions.Based on genetic judgements，most scientists believe they first existed in Central Asia.But previously，the oldest known big cat fossil was 3.6 million y
6、ears old and found in Africa.The new fossil findings were published in the November 13 issue of the science journal Proceedings of the Royal Society B：Biological Sciences.Tseng and his team were fossil hunting in the Himalayas in 2010 when they discovered some bones，including the buried cat skull.Th
7、e researchers were able to determine its age by studying the surrounding rocks and soil.The skull indicates that the animal was about the size of a clouded leopard，which can grow up to 50 pounds.In 2012，the team returned to unearth more cat bones.David Polly from Indiana University told the Associat
8、ed Press that the fossil is “convincingly older than the current record holder”He added that there could be even older big cat fossils in the Tibetan plateau to uncover.【语篇解读】本文讲述了最新考古发现一个大型猫科动物的颅骨化石。1What does the newlyunearthed skull prove?ABig cats might have their origins in Asia.BThe oldest fos
9、sil is 4.4 million years old.CThe snow leopard is the oldest big cat.DThe skull is of big cats direct ancestor.A推理判断题。由第二段最后一句“The fossil lends evidence to the belief that big cats existed in Asia and spread out from there.”可推知，该化石使我们相信大型猫科动物起源于亚洲，然后繁衍到其他地方。2What does the underlined word “predators”
10、 in paragraph 3 mean?ARelatives.BEnemies.CPartners. DProtectors.B词义猜测题。画线词所在句句意为：大型猫科动物位于食物链的顶端，所以几乎没有天敌。故选B。3How do the researchers know the skulls age?ABy measuring its size and forehead.BBy examining other bones around it.CBy studying its chemical composition.DBy exploring the rocks and soil arou
11、nd it.D细节理解题。由第四段第三句“The researchers were able to determine its age by studying the surrounding rocks and soil.”可知，研究者们通过研究化石周围的岩石和土壤来了解化石的年代。4Where was “the current record holder” in the last paragraph found?AAsia. BAfrica.CAmerica. DAustralia.B推理判断题。题干中引号内的词意为“现在的纪录保持者”，应该指的是新化石发现之前的最古老的化石；而第三段最后一
12、句“But previously，the oldest known big cat fossil was 3.6 million years old and found in Africa.”可知，现在的纪录保持者是在非洲发现的。BThe goal of every plant and animal is the same：to create the next generation.The way a plant makes another generation of its species is by making seeds.Flowers are the tools that plant
13、s use to make their seeds.The job of a flower is to help its pollinator put pollen(花粉)exactly in the right place at the right time to make a seed.When a plants flower succeeds in this，the plant gets to pass the secret for this success to the next generation，through the genetic code in its seeds! Whe
14、n a plant fails to grow up and make seeds，its genetic code does not get passed on.It becomes a loser in the game of life.The environment is constantly testing each plant.Competition for sunlight，water，nutrients and space is fierce.Herbivores(食草动物)are hungry and plants are their breakfast，lunch and d
15、inner! Only the strongest individuals survive long enough to reproduce.These survivors keep making seeds，letting the environment select the winners and losers.Through this selection process plants have evolved(进化)to survive life in every habitat on our planet.This evolution has filled even the harsh
16、est habitats with life，including cold high mountains.Although the pollination of a flower may appear to happen by accident，plants and pollinators have been practicing for millions of years to make sure that this “accident” happens.Often a plant and pollinator coevolve (evolve together)，adapting to(适
17、应)changes in each other to improve their own survival.A plant species may depend on a single species of pollinator to make its seeds.Likewise，many pollinators rely on one plant species to provide all the food for their young.【语篇解读】每种植物和动物的目的都是一样的，那就是创造下一代。本文主要讲述了植物是如何创造下一代的。5Which of the following i
18、s a necessary factor for a plant to become a winner in the game of life?AThe plant fails to grow up.BThe plant makes no seeds.CThere are no pollinators.DThe plants genetic code gets passed on.D细节理解题。根据第二段内容可知，A、B、C三个选项都是错误的，再结合该段倒数第二句“When a plant fails to grow up and make seeds，its genetic code doe
19、s not get passed on.”可知，遗传密码得以传递是植物在生存游戏中获胜的必要因素。故选D。6From the third paragraph we can infer that_Athe environment is very important for a plant to surviveBherbivores can increase the development of plantsConly the strongest plants can have seeds to reproduceD.sunlight，water，nutrients and space are e
20、qual for all the plantsA推理判断题。根据第三段第一句及本段内容可推断，环境对于植物的生存起非常重要的作用。7The underlined word “harshest” in the third paragraph probably means “_”Aseverest BbusiestCrichest Dmost valuableA词义猜测题。根据画线词后的“including cold high mountains”可判断，即使是在有生命的最“严酷的”栖息地，也充满了这种进化过程。8The last paragraph tells us a truth that_A
21、the pollination of a flower happens only by beesBplants rely on pollinators to provide all the food for their youngCplants and pollinators depend on each other to surviveD.pollinators depend on plants to make seedsC推理判断题。根据最后一段的内容可知，植物和传粉者是相互依存的。故选C。.阅读七选五If you are hungry，what do you do? Have your
22、favorite meal._1_ But you dont realize it，because your mind is busy thinking about your friends or favorite stars.If your mind is always hungry，it doesnt grow.When your mind fails to grow，creativity stops.This might be the reason why we all sometimes think “What happens next？”“Why cant I think？”_2_
23、Why reading but not watching TV? It is because reading has been the most educative tool used by us right from childhood.Since it helps with other parts of our life，we have to get help from reading.Once you read a book，you run your eyes through the lines and your mind tries to explain something to yo
24、u._3_ Now this seed is used by you to develop new ideas，although you dont realize it.If it is used many times，the same seed can give you great help to create a lot of things，which you would have never thought of in your wildest dreams!This is nothing but creativity._4_ When youve read widely enough，
25、you can start talking with your friends in English or any other language and find yourself able to freely use plenty of good right words.So dear friends，do give food for your mind by reading，reading and more reading._5_ Go and get a book!A.Now what are you waiting for?BReading can help you make more
26、 friends，too.CJust like your stomach，your mind is also hungry.DWhy not do some reading while you are hungry?EAlso this makes a significant contribution to your vocabulary.FThe interesting part of the book is stored in your mind as a seed.GHunger of the mind can be actually solved through wide readin
27、g.【语篇解读】本文论述了读书对我们的好处。1C根据上文的句子“If you are hungry，what do you do？”(如果你饿了，你会怎么做？)可知此处意为：就像你的胃，你的思想也会饥饿的。故选C。2G根据下文的句子“Why reading but not watching TV？”(为什么是阅读而不是看电视？)可知此处意为：要解决思想的饥渴我们要阅读。故选G。3F空后的句子“Now this seed is used by you to develop new ideas，although you.”中的this seed对应F项中的a seed。故选F。4E根据空后的句子“When youve read widely enough，you can start talking with your friends in English or any other language and find yourself able to freely.right words.”可知此处意为：它也对你的词汇量有很大的贡献。故选E。5A根据空后的句子“Go and get a book！”可知A项“现在你在等什么？”符合语境。故选A。