& Unit知识点 & “Millions of years ag...”习题详情
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Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs, the whole earth was warm and wet. There were green forests and they could find enough to eat. Later, parts of the earth became cold and dry, and the forests there died. Then dinosaurs could not find enough to eat. This must be one reason why dinosaurs died out.We can guess another reason. New kinds of animals came on the earth. Some had big brains and strong .They could kill dinosaurs.There may be other reasons that we don’t know about yet. Scientists are are trying to make more discoveries about dinosaurs.Dinosaurs were of many sizes and shapes. Some were as small as chickens, while some were about 90 feet long.There were also terrible rights between dinosaurs. They night have happened more than 100 million years ago. Though there was no man to see any of the fights, we can be told by the animal’s footprints(足迹)that fights did take place .【小题1】According to the passage, dinosaurs did exist only on the earth &&&&.A．for millions of year B．millions of years agoC．more than 100 million years agoD．when it was warm and wet somewhere【小题2】One reason why dinosaurs died out is that &&&&.A．there were too many dinosaurs B．parts of the earth became cold and dry C．the dead forests there could not supply them with enough food D．they couldn’t find enough go eat【小题3】One more reason why dinosaurs died out may be that &&&&.A．new kinds of animals came on the earth B．some fast and strong animals with big brains could kill them C．some dinosaurs were as small as chickensD．some big dinosaurs died in the fights【小题4】We can see from this passage &&&&.A．scientists are trying to make some dinosaurs B．dinosaurs are dangerous enough C．dinosaurs are worth studying D．scientists know nothing about dinosaursB&
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习题“Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs, the whole earth was warm an...”的分析与解答如下所示：
【小题1】B 文章第一句话“Millions of years ago dinosaurs lived on the earth.”可知恐龙生活于几百万年前。【小题2】D文章第一段介绍恐龙灭绝的一个原因是缺乏食物，而B项是导致食物缺乏的一个原因。【小题3】B第二段介绍恐龙灭绝的另一个原因是出现了更大、更强、更聪明的生物，它们有可能把恐龙杀灭。【小题4】C从文章第三段第二句话“Scientists are trying to make more discoveries about dinosaurs.”可知，科学家正在对恐龙进行更进一步的研究，由此推知恐龙值得研究。
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经过分析，习题“Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs, the whole earth was warm an...”主要考察你对“Unit 4 Exploring plants”
等考点的理解。
因为篇幅有限，只列出部分考点，详细请访问。
Unit 4 Exploring plants
与“Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs, the whole earth was warm an...”相似的题目：
--- Did you have any difficulty catching yesterday’s lecture? --- No. The professor spoke very clearly to make his speech easy &&&&.understoodunderstandunderstandingto understand
Put everything &&&&to you in your bag, not others.belongsbelongedbelongingto belong
The blue tits(山雀) have been inspecting the nest-box again this year. The male is the house-hunter but the female will make the final choice. He lands at the hole and turns his head to expose his white cheeks as a signal to attract the female from where she has been feeding. Among many birds that nest in holes, the male has a light-coloured patch on its plumage(鸟羽) which acts as signal for drawing the female’s attention to a suitable nesting-place. Unlike the blue tit, the redstart(红尾鸲) may be only the male that strikingly coloured and the female is not beautiful.
A few years ago I was lucky enough to spot a pair of redstarts in action in a Walsh wood. The male was leading an interested female to holes that he had previously(先前) checked out. He sat at the entrance of each hole and put his head on to show off his white forehead, or his head in to reveal(显露) his tail.
If the female failed to react to his visual signals, the male sometimes sang for extra effect, while gliding towards her on spread wings and tail. Once the female accepts by following the male through the hole the displays stop, you must be at the right place at the right time to watch them. 【小题1】How do the blue tits choose their nest?A．They choose their nest together.B．The male chooses their nest. C．The house-hunter chooses their nest. D．The female chooses their nest.【小题2】The writer was lucky to see &&&&. A．how the male made his tricksB．how an interested female played with the male happilyC．what the male displayed and won the femaleD．that the male tried his best but failed to attract the female【小题3】You can spot a pair of redstarts in a Walsh wood &&&&. A．at any timeB．regularlyC．in AprilD．occasionally【小题4】The writer is probably &&&&. A．a bird expert B．a bird-hunterC．a bird raiserD．a scientist&&&&
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欢迎来到乐乐题库，查看习题“Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs, the whole earth was warm and wet. There were green forests and they could find enough to eat. Later, parts of the earth became cold and dry, and the forests there died. Then dinosaurs could not find enough to eat. This must be one reason why dinosaurs died out.We can guess another reason. New kinds of animals came on the earth. Some had big brains and strong .They could kill dinosaurs.There may be other reasons that we don’t know about yet. Scientists are are trying to make more discoveries about dinosaurs.Dinosaurs were of many sizes and shapes. Some were as small as chickens, while some were about 90 feet long.There were also terrible rights between dinosaurs. They night have happened more than 100 million years ago. Though there was no man to see any of the fights, we can be told by the animal’s footprints(足迹)that fights did take place .【小题1】According to the passage, dinosaurs did exist only on the earth ____.A．for millions of year B．millions of years agoC．more than 100 million years agoD．when it was warm and wet somewhere【小题2】One reason why dinosaurs died out is that ____.A．there were too many dinosaurs B．parts of the earth became cold and dry C．the dead forests there could not supply them with enough food D．they couldn’t find enough go eat【小题3】One more reason why dinosaurs died out may be that ____.A．new kinds of animals came on the earth B．some fast and strong animals with big brains could kill them C．some dinosaurs were as small as chickensD．some big dinosaurs died in the fights【小题4】We can see from this passage ____.A．scientists are trying to make some dinosaurs B．dinosaurs are dangerous enough C．dinosaurs are worth studying D．scientists know nothing about dinosaurs”的答案、考点梳理，并查找与习题“Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs, the whole earth was warm and wet. There were green forests and they could find enough to eat. Later, parts of the earth became cold and dry, and the forests there died. Then dinosaurs could not find enough to eat. This must be one reason why dinosaurs died out.We can guess another reason. New kinds of animals came on the earth. Some had big brains and strong .They could kill dinosaurs.There may be other reasons that we don’t know about yet. Scientists are are trying to make more discoveries about dinosaurs.Dinosaurs were of many sizes and shapes. Some were as small as chickens, while some were about 90 feet long.There were also terrible rights between dinosaurs. They night have happened more than 100 million years ago. Though there was no man to see any of the fights, we can be told by the animal’s footprints(足迹)that fights did take place .【小题1】According to the passage, dinosaurs did exist only on the earth ____.A．for millions of year B．millions of years agoC．more than 100 million years agoD．when it was warm and wet somewhere【小题2】One reason why dinosaurs died out is that ____.A．there were too many dinosaurs B．parts of the earth became cold and dry C．the dead forests there could not supply them with enough food D．they couldn’t find enough go eat【小题3】One more reason why dinosaurs died out may be that ____.A．new kinds of animals came on the earth B．some fast and strong animals with big brains could kill them C．some dinosaurs were as small as chickensD．some big dinosaurs died in the fights【小题4】We can see from this passage ____.A．scientists are trying to make some dinosaurs B．dinosaurs are dangerous enough C．dinosaurs are worth studying D．scientists know nothing about dinosaurs”相似的习题。扫二维码下载作业帮
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We have been friends (). A.last year B.one year ag. C.since we met last year D.when we met last year
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C 【解析】句意:自从去年我们相遇我们就成为朋友了。本题考查状语从句。“since+-般过去时的句子”常与现在完成时连用,故选C。
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& Not long ago,the only time you could see a robot was when you were reading a novel or watching a movie such as Star Wars(《星球大战》).Today,however,a lot of things in science stories have been science facts.Robotsare starting to appearin our everyday lives.These robots have different sizes,shapes,and colors.But they all have the same type of manmade “brain”.Leading the robot revolution are industrial(工业的) robots that work in factories.Industrial robots can do different kinds of jobs that are often boring and sometimes dangerous. Robots are also coming to American homes,though not as quickly as they are entering factories.These robots aren’t as friendly and bright as those you saw in Star Wars.But,their makers say,today’s home robots “walk”,sense objects(感知物体) in their way (and sometimes knock into them),and even carry objects (which they sometimes drop).Well,nobody is perfect.& We may laugh at home robots today,but some day they may see and hear better than humans do.We humans can only see certain wavelengths(波长) of light,and hear certain sounds.That’s because the abilities of our eyes and ears are limited(有限的).Robots,however,need not have the same limits as we have.Robots may alsobe equipped with devices that pick up information humanscan’t.Tounderstand what their sensing devices(传感器) pick up is a hard job.Remember,manmade brains handle information, including all kinds of data(数据),as zeroes and ones.Imagine the difficulty in trying to explain to a robot what a football looks likeusing only zeroes and ones.1.Which of the followings about robots is true?A.They can be used in many ways,acting in the movies,for example.B.Robots are coming into the families as quickly as into the factories.C.Today’s robots are so perfect that they can do almost anything for us.D.Many boring or sometimes dangerous work are now being done by robots in industry.2.From the passage,we can see that factory robots _________.A.help to improve other types of robotsB.are most active in industrial revolutionC.are playing a more important role than other types of robotsD.are the tallest type among robots3.It seems that home robots are __________.A.more widely used than factory robotsB.less common than factory robotsC.capable of doing any kind of houseworkD.free from making mistakes while performing(执行) duties4.The development of robots suggests that __________.A.science and technology are developing fastB.people are interested in new inventionsC.machines are more capable than humansD.robots can be very interesting5.The biggest difficulty in making a robot working like a human being is to_______.A.shape it the exact like a real manB.have it has the same intelligence as human beingsC.make it think the same way a man doesD.transform the real matters in the form of zeros and ones
&& Not long ago,the only time you could see a robot was when you were reading a novel or watching a movie such as Star Wars(《星球大战》).Today,however,a lot of things in science stories have been science facts.Robots are starting to appear in our everyday lives.These robots have differentsizes,shapes,and colors.But they all have the same type of manmade “brain”.Leading the robot revolution are industrial(工业的) robots that work in factories.Industrial robots can do different kinds of jobs that are often boring and sometimes dangerous.Robots are also coming to American homes,though not as quickly as they are entering factories.These robots aren’t as friendly and bright as those you saw in Star Wars.But,their makers say,today’s home robots “walk”,sense objects(感知物体) in their way (and sometimes knock into them),and even carry objects (which they sometimes drop).Well,nobody is perfect.&& We may laugh at home robots today,but some day they may see and hear better than humans do.We humans can only see certain wavelengths(波长) of light,and hear certain sounds.That’s because the abilities of our eyes and ears are limited(有限的).Robots,however,need not have the same limits as we have.Robots may also be equipped with devices that pick up information humans can’t.To understand what their sensing devices(传感器) pick up is a hard job.Remember,man made brains handle information,including all kinds of data(数据),as zeroes and ones.Imagine the difficulty in trying to explain to a robot what a football looks likeusing only zeroes and ones.1.From the passage,we can see that factory robots __________.A.help to improve other types of robotsB.are most active in industrial revolutionC.are playing a more important role than other types of robotsD.are the tallest type among robots2.It seems that home robots are _________.A.more widely used than factory robotsB.less common than factory robotsC.capable of doing any kind of houseworkD.free from making mistakes while performing(执行) duties3.The development of robots suggests that _______.A.science and technology are developing fastB.people are interested in new inventionsC.machines are more capable than humansD.robots can be very interesting
&D&&&&& Not long ago，the only time you could see a robot was when you were reading a novel or watching a movie such as Star Wars(《星球大战》)．Today，however，a lot of things in science stories have been science facts.Robots are starting to appear in our everyday lives.These robots have different sizes，shapes，and colors.But they all have the same type of man&made “brain”．Leading the robot revolution are industrial(工业的) robots that work in factories.Industrial robots can do different kinds of jobs that are often boring and sometimes dangerous.Robots are also coming to American homes，though not as quickly as they are entering factories.These robots aren't as friendly and bright as those you saw in Star Wars.But，their makers say，today's home robots “walk”，sense objects(感知物体) in their way (and sometimes knock into them)，and even carry objects (which they sometimes drop)．Well，nobody is perfect.&&&&& We may laugh at home robots today，but some day they may see and hear better than humans do.We humans can only see certain wavelengths(波长) of light，and hear certain sounds.That's because the abilities of our eyes and ears are limited(有限的)．Robots，however，need not have the same limits as we have.Robots may also be equipped with devices that pick up information humans can't.To understand what their sensing devices(传感器) pick up is a hard job.Remember，man&made brains handle information，including all kinds of data(数据)，as zeroes and ones.Imagine the difficulty in trying to explain to a robot what a football looks likeusing only zeroes and ones.(1)Which of the following about robots is true?A．They can be used in many ways，acting in the movies，for example.B．Robots are coming into the families as quickly as into the factories.C．Today's robots are so perfect that they can do almost anything for us.D．Many boring or sometimes dangerous work are now being done by robots in industry.(2)From the passage，we can see that factory robots ______.A．help to improve other types of robotsB．are most active in industrial revolutionC．are playing a more important role than other types of robotsD．are the tallest type among robots(3)It seems that home robots are ______.A．more widely used than factory robotsB．less common than factory robotsC．capable of doing any kind of houseworkD．free from making mistakes while performing(执行) duties(4)The development of robots suggests that ______.A．science and technology are developing fastB．people are interested in new inventionsC．machines are more capable than humansD．robots can be very interestingWe fitted the theoretical FT ? ? ? k ?? function for fcc Ag first to experimental fcc Ag using different k -weightings at different fixed values of S 2 o for the first coordination shell, i.e., N = 12. Because S 2 o is k -independent, its correct value is at the point where the ? 2 vs S 2 o lines at different k -weightings meet, giving us S 2 o ? 0.79. Similar analyses were conducted for the x = 2.13 and 5.59 samples and we obtain values of 0.76 ± 0.02 and 0.77 ± 0.02, respectively, for S 2 o . Because S 2 o is an atomic property, it is expected that the values in x = 2.13 and 5.59 will have the same value as fcc Ag, and so their slightly smaller S 2 o value with respect to Ag is, in fact, a reflection of a slightly smaller coordination number ? which had been set to the value 12 in the fit ? . We can, therefore, say that the coordination number in x = 2.13 and 5.59 is at most ? 6% smaller than that of fcc Ag, or 11.25 out of the 12 nearest neighbors. A slightly smaller coordination number suggests that there are defects within the segregated Ag and/or there are observable surface Ag atoms, as the particles of segregated Ag are still at the nanoscale. Both of these possibilities are likely in nonequilibrium process of Li intercalation. The remaining difference in amplitude of B 1 between fcc Ag, x = 5.59 and x = 2.13 must therefore come from the ? 2 parameter, which increases by ? 11% from fcc Ag to Li 2.13 Ag 2 V 4 O 11 . With Li insertion, the increase in the amplitude of the nearest neighbor Ag–Ag peak ? B 1 in Fig. 3 ? and, correspondingly, all the higher coordination peaks ? B 2 –B 4 ? comes from an increase in ordering of the segregating Ag. Finally, the best fit was achieved by allowing the nearest-neighbor Ag–Ag distance to decrease by 0.02 ?. The shift further points to a nonequilibrium fcc-like arrangement of Ag atoms in Li 2.13 Ag 2 V 4 O 11 and Li 5.59 Ag 2 V 4 O 11 . In spite of the fact that the FT ? ? ? ? k ?? function from Li 0.72 Ag 2 V 4 O 11 appears to be a linear combination ? LC ? of those from Ag and SVO, the best-fit simulation, shown in Fig. 4, fails to reconstruct its region “A”. The LC simulation overestimates the amplitude of the region “A”, which is expected because the LC does not take into account the effect of Li, which is a weak backscatterer of the photoelectrons ? smaller value of F j ? , and also modifies the local structure. We do not have a structural model for Li intercalated SVO, and so for Li 0.72 Ag 2 V 4 O 11 we are not able to deconvolute strictly the fcc Ag contribution to FT ? ? ? ? k ?? . For an independent perspective, we have done an analysis of the Ag X-ray absorption near-edge structure ? XANES ? which, unlike XAFS, is highly sensitive to the details of the shallow electronic states of the central atom. As revealed by the FT ? ? ? ? k ?? functions discussed above, the XANES data also show that Ag atoms segre- gate from an SVO environment to metallic Ag with increased lithiation, with the reaction nearly complete with 2.13 mol. of Li per SVO. The Ag K edge XANES normalized to a per atom basis are shown for SVO, lithiated SVO, and Ag foil samples in Fig. 5. The presence of isosbestic points, as indicated by the arrows, indicate the fact that the Ag segregation from SVO is stoichiometrically linear with SVO and Ag as the endpoints. The normalized Ag K edge XANES data for the lithiated samples were fit to an LC of XANES data from Ag-foil and SVO. From the LC XANES fit there is 36%, 90%, and 95% of fcc Ag in x = 0.72, 2.13, and 5.59 samples, respectively as depicted in Fig. 6. These results are in apparent agree- 24 ment with data published by Leising et al. It is also clear from LC XANES that, in Li 0.72 Ag 2 V 4 O 11 , the oxidation state in the 64% of Ag remains SVO-like ? with a nominally +1 oxidation state ? , even though the structural environment, as we have seen from XAFS in Fig. 4, does not. At the same time, some Ag atoms in Li 2.13 Ag 2 V 4 O 11 remain in the nominally +1 oxidation state ? ? 10% of Ag is in SVO-like environment ? even as nearly all the Ag has fully segregated to an fcc-Ag-like structure. Ag reduction continues to at least Li 5.59 Ag 2 V 4 O 11 . Alternatively, a small amount of Ag +1 could remain in the highly lithiated sample due to lack of electrochemical contact of some of the original SVO particles, as hypothesized in the context of the 51 V NMR results.Join ResearchGate to access over 30 million figures and 100+ million publications – all in one place.Copy referenceCopy captionEmbed figurePublished in
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The spectrum exhibits two lines at 0 and ?1.6 ppm. Because diamagnetic lithium environments, such as those present in the electrolyte salt (LiPF 6 ), solid electrolyte interphase (SEI), and lithium fluoride LiF, all resonate at approximately 0 ppm [49,51], the definitive assignment of the lines at 0 and ?1.6 ppm is not obvious. By analogy with Sideris work [49], the line at ?1.6 ppm could be related to inserted lithium species, the second line being related to lithium from the electrolyte. ABSTRACT: Li-CFx battery using a specific fluorinated nanocarbon as cathode material exhibits a capacity exceeding the expected theoretical value when used as an electrode material in primary lithium battery. Carbon nanodiscs were partially fluorinated by atomic fluorine released by thermal decomposition of TbF4, and the capacity of this material was up to 1180 mAh.g-1, whereas a theoretical value of 847 mAh.g-1 for the CF0.95 sample was calculated. The obtained value is also higher than the maximum one of 865 mAh.g-1 expected for CF1 carbon fluorides. The discharge mechanism was investigated using mainly SEM and solid state NMR in order to understand this “extra-capacity”. Both the un-fluorinated carbon and the LiF covering, which is formed outside the carbon lattice during the discharge mechanism, play a key role for the achievement of the extra-capacity by the consumption of Li+ to form Li2F+ species stabilized by the carbon host structure formed after the electrochemical de-fluorination. Full-text · Article · Jul 2015 +1 more author...The 31 P shifts were much larger than the corresponding 7 Li shifts, demonstrating an increased sensitivity to the P-O-M bond covalency which may ultimately be correlated with the degree of Jahn-Teller distortions present in the material, electrochemical performance, and mechanisms that lead to failure. Leifer et al. [105]. used 7 Li MAS NMR to study the structure of lithiated silver vanadium oxide, Li x Ag 2 V 4 O 11 , where x = 0.72, 2.13, and 5.59. ABSTRACT: Despite their spectacular success in portable electronics applications, continued technical advances of lithium-ion batteries are crucial to establishing large-scale storage applications such as electric vehicles and enabling development of renewable intermittent energy sources, i.e., wind and solar. Paramount considerations in realizing scaled-up battery systems are safety, cost, energy density, and service lifetime. Some of these applications also require rapid charge and discharge capability. To move beyond the current generation of lithium-ion batteries, it is necessary to understand some of the outstanding materials issues of the individual components (i.e., electrodes and electrolytes) as well as the battery system as a whole where the components interact under conditions of elevated temperature and electric current flow. Full-text · Chapter · Nov 2013 · Journal of Solid State ChemistryThe 31 P shifts were much larger than the corresponding 7 Li shifts, demonstrating an increased sensitivity to the P-O-M bond covalency which may ultimately be correlated with the degree of Jahn-Teller distortions present in the material, electrochemical performance, and mechanisms that lead to failure. Leifer et al. [105]. used 7 Li MAS NMR to study the structure of lithiated silver vanadium oxide, Li x Ag 2 V 4 O 11 , where x = 0.72, 2.13, and 5.59.
Full-text · Chapter · Jan 2012 · Journal of Solid State ChemistryTechnical details concerning successful implementation of the lithium/SVO battery in ICDs have been described. (5,6,7,8,9,10) Further, the discharge process of SVO in a lithium battery has been investigated by several methods including titration, x-ray powder diffraction and solid state NMR.(10,11,12,13) The discharge process of SVO initiates with the competitive reduction of Ag + to Ag 0 and of V 5+ to V 4+ and then proceeds to some reduction of V 4+ to V 3+ . ABSTRACT: This report details the chemical and associated electrical resistance changes of silver vanadium phosphorous oxide (Ag(2)VO(2)PO(4), SVPO) incurred during electrochemical reduction in a lithium based electrochemical cell over the range of 0 to 4 electrons per formula unit. Specifically the cathode electrical conductivities and associated cell DC resistance and cell AC impedance values vary with the level of reduction, due the changes of the SVPO cathode. Initially, Ag(+) is reduced to Ag(0) (2 electrons per formula unit, or 50% of the calculated theoretical value of 4 electrons per formula unit), accompanied by significant decreases in the cathode electrical resistance, consistent with the formation of an electrically conductive silver metal matrix within the SVPO cathode. As Ag(+) reduction progresses, V(5+) once the SVPO reduction process progresses to where the reduction of V(5+) to V(4+) is the dominant process, both the cell and cathode electrical resistances then begin to increase. If the discharge then continues to where the dominant cathode reduction process is the reduction of V(4+) to V(3+), the cathode and cell electrical resistances then begin to decrease. The complex cathode electrical resistance pattern exhibited during full cell discharge is an important subject of this study. Full-text · Article · Oct 2010 +1 more author... Full-text · Article · Jan 2009 · Journal of Solid State ChemistryABSTRACT: The transport properties and lithium insertion mechanism into the first mixed valence silver-copper oxide AgCuO2 and the B-site mixed magnetic delafossite AgCu0.5Mn0.5O2 were investigated by means of four probes DC measurements combined with thermopower measurements and in situ XRD investigations. AgCuO2 and AgCu0.5Mn0.5O2 display p-type conductivity with Seebeck coefficient of Q = +2.46 and +78.83 mu V/K and conductivity values of sigma = 3.2 x 10(-1) and 1.8 x 10(-4) S/cm, respectively. The high conductivity together with the low Seebeck coefficient of AgCuO2 is explained as a result of the mixed valence state between Ag and Cu sites. The electrochemically assisted lithium insertion into AgCuO2 shows a solid solution domain between x = 0 and 0.8Li(+) followed by a plateau nearby 1.7 V (vs. Li+/Li) entailing the reduction of silver to silver metal accordingly to a displacement reaction. During the solid solution, a rapid structure amorphization was observed. The delafossite AgCu0.5Mn0.5O2 also exhibits Li+/Ag+ displacement reaction in a comparable potential range than AgCuO2; however, with a prior narrow solid solution domain and a less rapid amorphization process. AgCuO2 and AgCu0.5Mn0.5O2 provide a discharge gravimetric capacity of 265 and 230 mA h/g above 1.5 V (vs. Li+/Li), respectively, with no evidence of a new defined phases. Full-text · Article · Feb 2009