exercise1.2

Exercise1.2I V −Fig.E1.2Problem:Is there another way to derive the sheet resistance expression?Solution:Consider a sample of thickness t and resistivity ρ.The four probes are arranged as in Fig.E1.2.Current I is injected at probe I +and spreads out cylindrically symmet-ric.By symmetry and current conservation,the current density at distance r from the probe isJ =I 2πrt The electric field isE =Jρ=Iρ2πrt =−dV drIntegrating this expression gives the voltage drop between probes V +and V −,located atdistances s 1and s 2from I +asV s 2V s 1dV =−Iρ2πts 2s 1dr r ⇒V s 1−V s 2=V 12=Iρ2πt ln s 2s 1By the principle of superposition,the voltage drop due to current injected at I −isV 34=−Iρ2πt ln s 3s 4 leading toV =V 12−V 34=Iρ2πt ln s 2s 3s 1s 4For a collinear arrangement with s 1=s 4=s and s 2=s 3=2sρ=πt ln (2)V I ;R sh =πln (2)V IExercise 1.3Problem:What does sheet resistance mean and why does it have such strange units?Fig.E1.3Solution:To understand the concept of sheet resistance,consider the sample in Fig.E1.3. The resistance between the two ends is given byR=ρLA=ρLW t=ρtLWohmsSince L/W has no units,ρ/t should have units of ohms.Butρ/t is not the sample resis-tance.To distinguish between R andρ/t,the ratioρ/t is given the units of ohms/square and is named sheet resistance,R sh.Hence the sample resistance can be written asR=R sh LWohmsThe sample is sometimes divided into squares,as in Fig.E1.4.The resistance is then given asR=R sh(ohms/square)×Number of squares=5R sh ohmsLooking at it this way,the“square”cancels.The sheet resistance of a semiconductor sample is commonly used to characterize ion implanted and diffused layers,metalfilms,etc.The depth variation of the dopant atoms need not be known,as is evident from Eq.(1.19).The sheet resistance can be thought of as the depth integral of the dopant atom density in the sample,regardless of its vertical spatial doping density variation.A few sheet resistances are plotted in Fig.E1.5versus sample thickness as a function of sample resistivity.Also shown are typical values for Al,Cu and heavily-doped Si.Exercise1.4Problem:For the carrier density profiles in Fig.E1.6,do the sheet resistances of thethreelayers differ?Fig.E1.410−3101010310−210−1100101102S h e e t R e s i s t a n c e (Ω/s q u a r e )Thickness (cm)Fig.E1.5Solution:Eq.(1.19)shows the sheet resistance to be inversely proportional to theconductivity-thickness product.For constant mobility,R sh is inversely proportional to the area under the curves in Fig.E1.6.Since the three areas are equal,this implies that R sh is the same for all three cases.In other words,it does not matter what the carrier distribution is,only the integrated distribution matters for R sh .Four-point probe measurements are subject to further sample size correction factors.For circular wafers of diameter D ,the correction factor F 2in Eq.(1.12)is given by 16F 2=ln (2)ln (2)+ln {[(D/s)2+3]/[(D/s)2−3]}(1.20)F 2is plotted in Fig.1.6for circular wafers.The sample must have a diameter D ≥40s for F 2to be unity.For a probe spacing of 0.1588cm,this implies that the wafer must be at least 6.5cm in diameter.Also shown in Fig.1.6is the correction factor for rectangular samples.6The correction factor 4.532in Eq.(1.17)is for collinear probes with the current flowing into probe 1,out of probe 4,and with the voltage sensed across probes 2and 3.For the current applied to and the voltage sensed across other probes,different correction factors obtain.17For probes perpendicular to and a distance d from a non-conducting boundary ,the correction factors,for infinitely thick samples,are shown in Fig.1.7.2It is obvious from the figures that as long as the probe distance from the wafer boundary is atleastn (x )Fig.E1.600102030400.20.40.60.81F 2D /sFig.1.6Wafer diameter correction factors versus normalized wafer diameter.For circular wafers:D =wafer diameter;for rectangular samples:D =sample width,s =probe spacing.0.511.52F 31, F 32, F 33, F 34d /sFig.1.7Boundary proximity correction factors versus normalized distance d (s =probe spacing)from the boundary.F 31and F 32are for non-conducting boundaries,F 33and F 34are for conducting boundaries.three to four probe spacings,the correction factors F 31to F 34reduce to unity.For most four-point probe measurements this condition is easily satisfied.Correction factors F 31to F 34only become important for small samples in which the probe is,of necessity,close to the sample boundary.Other corrections must be applied when the probe is not centered even in a wafer of substantial diameter.16For rectangular samples it has been found that the sensitivity of the geometrical correction factor to positional error is minimized by orienting the probe with its electrodes within about 10%of the center.11For square arrays the error is minimized by orienting the probe array with its electrodes equidistant from the midpoints of the sides.There is also an angular dependence of the placement of a square array on the rectangular。

［教材习题研讨］方法点拨INTRODUCTION[P3] Exercise 21.architect2.locatendmark4.writer5.gallery6.scuplture7.ancient[P3] Exercise 31.Paris，Athens2.Barcelona3.Paris4.Paris，Florence，Athens5.Athens[P3] Exercise 4True：1. 2. 5. 7.False：3. 4. 6. 8.FUNCTION[P4] Exercise 21.on2.across3.between4.on5.off[P4] Exercise 41.between2.north3.south4.between5.westGRAMMAR[P5] Exercise 21.Florence is visited by a million tourists each year.2.London was visited by ten million people last year.3.The Mona Lisa was painted by Leonardo da Vinci.4.The Mona Lisa wasn’t painted by Picasso.5.The Great Wall of China was built by thousands of workers.[P5] Exercise 31.No，it isn’t.It is located in Paris.2.No，it isn’t.It is situated on the River Seine.3.No，it isn’t.It is visited by a million tourists on every year.4.No，it isn’t.Athens is known as the birthplace of Western civilization.5.No，it wasn’t.It was built 2400 years ago.GRAMMAR[P7] Exercise 21.are playing2.are having3.lives，live[P7] Exercise 4 辨析词义，准确理解单词，并注意记忆积累，尤其是一个同义的“人”和“语言”形式上的区别。

Unit 1 What’s the matter?一、基础知识1.What’s the matter? 怎么啦？出什么事情了？【解析】matter/ ' mætə(r)) /n.问题；事情What’s the matter with you?= What’s the trouble with you? = What’s wrong with you?你怎么了？【注】：matter 和trouble 为名词，其前可加the 或形容词性物主代词，wrong 是adj. 不能加the【用法】用于询问某人有什么病或某人遇到什么麻烦、问题其后跟询问对象时，与介词with 连用。

即：What’s the matter with sb.? = What’s your trouble?= What’s up? = What happens to sb.?—What’s the matter with you ? —I have a bad cold.2.I had a cold.我感冒了。

have a cold=catch a cold=have the flu感冒have a fever 发烧have a cough咳嗽have a stomachache胃疼，肚子疼have a toothache牙疼have a headache头疼3.身体部位+ache（疼痛）构成新的复合词stomach+ache=stomachachehead+ache=headachetooth+ache=toothacheback+ache=backache后背痛4.much too+ 形容词，意为太...... ，too much+名词，意为很多，大量。

5.enough【形容、副词】足够的/地，enough放在名前后，形副后。

good enough足够好enough money=much money6.lie down躺下，lie 躺，躺着，过去式lay；lie说谎，过去式lied7.maybe ―或许‖，常用于句首，表示可能性，后加句子。

exercise的用法总结一、exercise的基本含义与用法在英语中，动词 "exercise" 是一个非常常见且多功能的词汇。

它可以表示身体活动、进行锻炼，还可以指使命令、思考、使用和执行等意思。

1. 表示身体活动和进行锻炼首先，"exercise" 最常见的用法就是表示身体活动和进行锻炼。

例如：- I love to exercise in the morning to start my day off right.（我喜欢早上锻炼来开始我的一天。

）- They go to the gym every evening to exercise and stay fit.（他们每晚去健身房锻炼以保持健康。

）2. 指使命令或表示执行其次，"exercise" 还可用于表达指使命令或表示执行某种行为。

例如：- The teacher asked the students to exercise caution while working in the chemistry lab.（老师要求学生们在化学实验室里工作时要小心。

）- The company exercised their right to terminate the contract due to breach of agreement.（公司行使了他们终止合同的权利，因为存在协议违反行为。

）3. 表示思考、使用和运用此外，"exercise" 还可用于表示思考、使用和运用某种技能或知识等方面的情况。

例如：- You should exercise critical thinking skills when analyzing complex problems.（当分析复杂问题时，你应该运用批判性思维技能。

）- The detective carefully exercised his reasoning abilities to solve the murder case.（侦探小心地运用推理能力来解决谋杀案。

Write on ANSWER SHEET THREE a note of about 50-60 words based on the following situation:One of your foreign friends Ann plans to go sightseeing in China. You have just come back from a place which you think she might enjoy. Write a note to advise her to go to this place.Marks will be awarded for content, organization, grammar and appropriateness.参考April 20, 2013Dear Ann,I heard that you are planning to go sightseeing in China, and I want to recommend you a good place. I just came back from Lijiang, which has beautiful landscape, kind people and interesting custom. Two ethnic minorities are living there, so you can buy many goods made by them and in the riverside bars you can watch shows given by them. You will have a lot of fun there.LilyIt is reported that mental health has become a troublesome issue. The number of people committing suicide is on the rise. You are required to analyze this phenomenon and contribute some suggestions on how to keep psychologically healthy.Write on ANSWER SHEET THREE a composition of about 200 words on the following topic:How to Keep Psychologically Healthy?You are to write in three parts.In the first part, state specifically what your view is.In the second part, provide one or two reasons to support your idea OR describe your idea.In the last part, bring what you have written to a natural conclusion or a summary.Marks will be awarded for content, organization, grammar and appropriateness. Failure to follow the instructions may result in a loss of marks.参考How to Keep Psychologically Healthy?Nowadays more and more people are concerned about mental health issue. It is reported that the number of people committing suicide is on the rise. Many of them committed suicide just because of some little frustration such as failing an exam. If they had paid more attention to their mental health, they might not have reacted in such an extreme way.How to keep ourselves psychologically healthy? First, we should adjust ourselves to the new conditions. When we go to a university as freshmen, or go to work in a strange city, we may become nervous because everything is so unfamiliar. The only way out is to adjust ourselves to the new conditions and shake off the anxiety quickly. Second, we should know our-selves well and admit that we are just ordinary people. Knowing that ordinary people may not be good at everything, we can easily accept some small failures in our lives. Third, we should try to share our feelings with friends. By doing this, we are assured that any difficulty can be solved since we are not alone.It is very important for us to be psychologically healthy, and we should pay more attention to our mental health.Write on ANSWER SHEET THREE a note of about 50-60 words based on the following situation:You have heard that your friend, Jim, wishes to sell his bike. Write him a note expressing your interest in it, asking him about its condition and offering a price for it.Marks will be awarded for content, organization, grammar and appropriateness.参考April 20, 2013Dear Jim,I have heard that you wish to sell your bike. At the moment I just need a bike by which I can go to do my part-time job on the weekend. Would you please tell me what color your bike is and how well it works? And is it possible that I buy it at the cost of 50 yuan?MaryHelping strangers used to be considered as a virtue. But nowadays people tend to be very cautious of strangers. They are afraid that helping others can sometimes bring them trouble. What’s your opinion?Write on ANSWER SHEET THREE a composition of about 200 words on the following topic:Should We Help Strangers?You are to write in three parts.In the first part, state specifically what your opinion is.In the second part, support your opinion with appropriate details.In the last part, bring what you have written to a natural conclusion or a summary.Marks will be awarded for content, organization, grammar and appropriateness. Failure to follow the instructions may result in a loss of marks.参考Should We Help Strangers?We used to appreciate those who like to help strangers, but nowadays people tend to be very cautious of strangers, because they are afraid that helping others can sometimes bring them trouble. In my opinion, we should try our best to help others in a reasonable way.We should try to help others, no matter they are strangers or not. First, helping others is a virtue, and it will make our society more harmonious. Just imagine what a terrible world it would be if everyone was coldhearted! Second, to some extent, helping others is helping oneself. We may come across some trouble and need others’ help some day. If everyone t urns a blind eye to our trouble and turns a deaf ear to our appeal for aid just because we are strangers to them, what shall we do at that time? Therefore, we should be glad to help others.However, helping others may sometimes bring us trouble or even put us in danger. So when we are helping others, we should also protect ourselves and offer our help in an appropriate way. For example, to help someone who was robbed, calling the police is a much wiser way than chasing the robbers alone.Write on ANSWER SHEET THREE a note of about 50-60 words based on the following situation:Your friend, Ann, just lost her grandmother, and is feeling very sad about it. Write a note to comfort her.Marks will be awarded for content, organization, grammar and appropriateness.Recently some banks extend their business to university campus and offer credit cards to students. A lot of people worry that credit cards may ring harm to students, while others don’t think so. What is your opinion?Write on ANSWER SHEET THREE a composition of about 200 words on the following topic:Will Credit Cards Bring Harm to the Students?You are to write in three parts.In the first part, state specifically what your opinion is.In the second part, support your opinion with appropriate details.In the last part, bring what you have written to a natural conclusion or a summary.Marks will be awarded for content, organization, grammar and appropriateness. Failure to follow the instructions may result in a loss of marks.。

大学视听说welearn答案一、引言大学视听说是一门重要的语言课程，旨在提高学生的听力、口语和阅读能力。

本文档将为大家提供welearn平台上大学视听说课程的答案，帮助同学们更好地完成课程任务。

我们将涵盖不同主题的答案，以帮助学生学习和了解课程内容。

二、Unit 11.1 Listening1.1.1 Exercise A1.bagels and cream cheese2.black coffee3.panini4.tea5.donuts1.1.2 Exercise B1.7:00 am2.Studying math and economics3.Reading for a philosophy class4.Studying for a chemistry exam5.Going to the gym1.2 Speaking1.2.1 Exercise A1.I’m interested in learning about different cultures.2.I like watching movies and reading books.3.I enjoy playing sports, especially basketball.4.I’m good at solving puzzles and riddles.5.I’m skilled in playing the guitar.1.2.2 Exercise B1.My favorite subject is English because I enjoy reading and writing.2.I like history because it helps me understand the world we live in.3.Math is my favorite subject because I find it challenging and rewarding.4.I enjoy biology because I find the study of living organisms fascinating.5.I’m interested in psychology because I like understanding human behavior.三、Unit 22.1 Listening2.1.1 Exercise A1.The Asian Art Museum2.Redwood National Park3.The Golden Gate Bridge4.Union Square5.Alcatraz Island2.1.2 Exercise B1.It originated in San Francisco.2.It was built in 1937.3.It connects San Francisco to Marin County.4.The bridge is painted international orange.5.It’s one of the most famous landmarks in the United States.2.2 Speaking2.2.1 Exercise A1.I have visited the Grand Canyon. It was an awe-inspiring experience.2.I have been to New York City. The vibrant atmosphere and iconic landmarks left a lasting impression on me.3.I have traveled to Paris. The art, architecture, and rich history of the city were incredible.4.I have explored Tokyo. The unique blend of tradition and modernity was fascinating.5.I have been to the Great Wall of China. Standing on the ancient structure was a humbling experience.2.2.2 Exercise B1.I would love to visit Rome to explore its rich historyand visit famous landmarks like the Colosseum.2.I would like to go to Rio de Janeiro to experience itsvibrant culture and attend the Carnival celebration.3.I dream of visiting the Maldives to relax on itsbeautiful beaches and snorkel in the crystal-clear waters.4.I hope to travel to the Serengeti in Tanzania to seethe incredible wildlife and witness the Great Migration.5.I plan to visit the Great Barrier Reef in Australia toadmire its biodiversity and go scuba diving.四、总结本文档提供了welearn平台上大学视听说课程的答案，涵盖了不同主题的听力和口语练习。

Exercise TwoDirections: Listen to the following passages carefully and try to fill in the missing words. You will hear the passages only once.1. Focus on the Main IdeaListening and reading require many skills in common. Finding the main idea in a paragraph is just one of these skills. The purpose of this talk is to discuss what a main idea is and how to (1) the main idea. Perhaps the best way to understand the main idea is to think of it as the (2) idea, or the most important idea which gives the paragraph purpose and (3) . That is to say, when you are trying to find the main idea, you are actually thinking about the purpose of the given paragraph: Is it to (4) you about something, to explain, to narrate? Or is it to (5) , to argue, to persuade, etc..? When you get the right answer for yourself, you are likely to have got the main idea.The main idea of a paragraph is usually (6) in what is called a topic sentence. More often than not, the topic sentence is the first sentence of a paragraph. It is followed by other sentences, containing supporting (7) . When a difficult idea is discussed or when the purpose of the paragraph is to (8)and convince, the topic sentence is sometimes placed at the end of the paragraph. If a paragraph has an (9) main idea, it does not have a stated topic sentence. The main idea is (10) at by the sentences in the paragraph as a whole.2. Don’t Attempt to Write Too MuchNote taking is a very (1) skill. But it is essential in listening. It helps us organize facts and retain concepts for later use. Taking good notes requires us to do two things quickly. First, to recognize the main topics; and second, to write down the important details and (2) examples as we hear and understand. In other words, our note-taking should keep (3) with the speaker‟s thinking process.The general principle for note taking is to (4) the language by shortening the words and sentences that we hear. It is important to remember that we should not attempt to write too much. That is to say, we should learn to write the (5) to give sufficient meaning. And we should also learn to choose an (6) time to write the notes quickly and lay them out clearly. Some commonly used Latin(7) are often very useful in note taking. For example, cf. --- compare or compare with; i.e.--- that is; e.g. --- for example; and etc. --- et cetera, and so on.One way to take notes of dialogues or conversations is to write down different speakers‟words in separate spaces, such as separate (8) or lines. This will help us (9) up each speaker‟s views and opinions correctly. Of course, note taking is a highly (10) skill. So we should make constant efforts to develop good ways of note taking which are effective and suitable to ourselves.3. Be Careful with NumbersQuick and accurate response to numbers is very important in daily communication. Telephone numbers, addresses, prices, temperatures, time and dates are all closely (1) with the use of numbers. Besides, numbers also play a very important part in (2) programs such as scientific stories, statistics update, and reports about ongoing events of various kinds. Although identification of numbers in (3) is usually easy, number identification through listening proves to be a big problem for many people. In actual listening, weare often required to get the numbers immediately after we hear them. And failure to get a correct number, sometimes a mere mistake in (4) , can seriously affect the understanding of the whole story and therefore cause severe (5) . The differences between million and billion, “teen‟s”and “ty‟s” are so great that no one can simply afford to ignore them.Numbers are sometimes read in different ways. For example, “seventeen point five million” or “seventeen million five hundred thousand” can also be read as “seventeen and one half million.” (6) training in numbers can help us get familiar with these different yet still regular ways of number (7) . For easy reading and writing, numbers of more than four digits are often separated by (8) into groups of three digits each. For example, 1,234,567 is one million, two hundred and thirty-four thousand, and five hundred and sixty-seven. Saying numbers over to yourselves after you hear them can increase your (9)to numbers. Numbers are all around us. Let us practice with numbers and learn to be (10) at numbers.4. How Is It Being Said---Formal or Informal LanguageA distinction is sometimes made between “formal” language situations and “informal” language situations. For example, a difference exists between a formal lecture and an informal (1) between friends. A lecture or a public address is expected to consist of relatively (2) speech. The language is more (3)than would be heard in informal conversation. Most lecturers and public speakers plan in advance what to say, and may have notes, or even a complete text, to guide them through the speech. The language they use tends more towards written language than that used in ordinary everyday talk. Their language is “formal” in contrast with the "informal" language of (4) produced speech.Unfortunately for the language learner, the division is not as neat as this. Frequently, for example, a lecturer delivering a very formal lecture (5) to informal language when making an aside or recounting an anecdote. Or a person describing a (6) matter to a friend over coffee may switch in and out of formal and informal styles. A doctor, for example, talking to a friend about his medical condition will probably describe the condition in fairly formal language and then go on to explain it in more informal language. Between the (7) , a range of formality or informality exists. This depends on the social setting, the relative ages and status of the speaker and listener, their attitudes to each other and the topic, to what extent they share the same (8) knowledge, and so on.Many language learners have limited experience of English language in informal situations. In their lessons they tend to use formal language. They have particular difficulty when switching to informal language within a formal situation. For the foreign language learner, (9) the importance of these scattered informal(10) is a problem. Therefore, focusing not only on what is said, but also on how it is being said, is an important listening skill.5. Making Use of Them--- Signals and FillersA speaker has many ways to indicate that he or she is moving from one point to another, or giving an example, or repeating a point, or whatever. To a language learner these signals can easily be (1) . Lecturers, for example, in a formal situation generally show clearly when a new point begins. They use expressions like "Secondly..." or "Then...". They may pause or make a (2) or move slightly. A change to a new point is often made by increased loudnessor a change of pitch. In spontaneous conversations, a different (3) indicates a new idea or the repeating of something the listener already knows. Students need to learn to listen to and watch the speaker for the "signals" in order to (4) the various parts of a speech.Pauses in speech give the listener time to think about what has been said and to relate it to what has gone before. Beginning students find it easier to listen to speakers who make long pauses between the "bits" of their utterances. Pause (5) depends on the speaker‟s speech habits, on the behavior and reactions of those listening, and on the speaker‟s (6) to work out what to say next. Long (7) in speech are often filled with sounds or expressions such as “er...”, “erm...”, “and er ...” sim ply to avoid long silences, which are thought to be (8) in English conversation. A good idea is to explain the use of these “fillers”, particularly to speakers of languages where long silences are a normal conversation feature. They can then (9) them and know that fillers such as “er”, “erm”, “and er...” are not part of the (10)message.6. Letting Things Go---Speed and VocabularyMany English language learners believe that the greatest difficulty with listening comprehension is that the listener cannot (1) how quickly a speaker speaks. They feel that the utterances disappear before they can sort them out, whereas the words in a written text remain on the page where the reader can (2)back at them or re-examine them thoroughly. This frequently means that students who are learning to listen cannot keep up. They are so busy working out the meaning of one part of what they hear that they miss the next part. Or they simply ignore a whole section because they fail to sort it all out quickly enough. Either way, they (3) .Another difficulty is that the listener is not always in a (4) to get the speaker to repeat what has been said. And, of course, repeats cannot be asked for when listening to the radio or watching television.Choice of vocabulary is in the hands of the speaker, not the listener, although in some circumstances it is possible to stop the speaker and ask for (5) . Sometimes, listeners can get the meaning of a word from its context. But very often, for people listening to a foreign language, an unknown word can be like a suddenly dropped (6) causing them to stop and think about the meaning of the word and thus making them miss the next part of the speech. In listening, it really is a case of “He who hesitates is lost!”Indeed, (7) to listen to what is coming, and letting things that have passed go rather than dwelling upon them, often gives surprising good results. Speakers often say things more than once, or rephrase them, or another speaker echoes what has been said. The listener who has not “stopped” to dwell on a half-missed point gets a second, or even third chance to fill the (8) in the message he or she is receiving.Students need to develop the skill of keeping up with the speaker (even being ahead of the speaker) even if this means letting parts which they have failed to sort out (9) . Professor H. H. Stern says that the good l anguage learner is the one who “can tolerate vagueness and (10) of knowledge.” This is especially true of good listeners.7. Thinking Ahead of the Speaker--- Anticipation HelpsListening is an extremely complex (1) activity. In this book Principles and Implications of Cognitive Psychology, Neisser defines listening as a “temporally extendedactivity” in which the listener “continuously develops more or less specific readiness for what will come next.” In other words, an effectiv e listener is constantly setting up a hypothesis in his mind, and also, he is constantly testing his hypothesis by (2)it with what he has heard in reality. If he hears what he has expected, he receives the information. But if what he hears is totally out of his expectation, he fails to get the message.The skill to anticipate what is coming in listening comprehension depends largely on the listener‟s (3)with the theme of the message. It also depends on the listener‟s (4) of the speaker as well as the setting. Obviously, when we listen to something that we already have some information about, it is generally a lot easier for us to take in the new information. Therefore, (5) preparation seems to have a big role to play in enhancing listening comprehension. Before actual listening, we could perhaps first give some thought to the topic, discuss it with others, read some (6) materials and do some vocabulary work. If we could make ourselves fully (7) for the forthcoming talks or lectures, we are more likely to become effective listeners.Of course, (8) beforehand is not at all enough. Active thinking must take place all the way through. In fact, we should always try to think ahead of the speaker. The ability to anticipate helps us in (9) and intelligent guesswork. It does not only enable us to know generally what a person is going to talk about in a certain situation, but also, interestingly enough, sometimes even exactly what a person‟s next (10)is going to be in a discussion!8. You Just Can’t Remember So Much ---Learn to Select, Learn to SimplifyAt a certain stage of English listening, some students may report a kind of unpleasant or even (1)experience. They say that while listening, they seem to understand everything that they hear, but as soon as the voice stops, all is gone! They say that they just can‟t remember what they heard, not to mention writing down or speaking out. What causes this problem? Is it also your complaint?Let us try to discuss the matter from two perspectives. First, knowing some difference between comprehension and (2) is important. When we learn a new language, we usually pass through at least three communication stages, namely, the one-way stage, the (3) two-way stage and the full two-way stage. Obviously, there‟s a gap between. Just as Brown and Terrell point out in their books on language learning and language teaching. “The (4) to produce an item should not be taken to mean that the learner cannot comprehend it.” Therefore, if we can comprehend what is being said to us, we have achieved the first (5) . That‟s quite encouraging! Secondly, of course, we‟ll have to move on. And we must be aware of some possible traps on our way to effective listening. When we listen, are we paying equal attention to every element in each utterance? Are we attempting to memorize and repeat and write down all the details in a passage? If so, we need to think for a while. Human memory can retain only a limited amount of information at a time. Therefore, only by learning to select and (6) can we possibly absorb what is really important and then remember what is the most (7) . In fact, when we listen, we usually listen with a purpose. Although it is sometimes necessary to get detailed and specific information on the subject, it is, more often than not, quite enough for us to (8) the key words and the main points. Furthermore, in the course of listening, if we are capable of (9) the complicated sentence structures into simple ones, interrogative into affirmative, or passive into active, our brain will certainly do amuch (10) job in helping our memory.9. Represent the Ideas Clear and Clean--- OutliningOutlining is a method of (1) and organizing ideas. It is a skill very useful to language learners when they are taking lecture notes, reading, or writing a paper. In listening, the skill of outlining reflects, to a certain extent, the listener‟s ability in understanding how the facts or ideas, or the (2) pieces of information are related to one another.People generally use a system of Roman numerals, Arabic numbers, and letters to show relationships. There is a kind of standard form for using these (3) to show which ideas are most important. The symbols used, in order of (4) importance, are Roman numerals ( I , II, III, ...) , capital letters (A, B, C, ...) , Arabic numbers (1, 2, 3, ...) , and numbers in parentheses [ ( 1 ) , (2) , (3) , ... ].The placement of the topics on paper is also important. The most important items are entered farther to the left. (5) items are entered farther and farther to the fight. Headings of (6) importance are indented the same distance from the left margin. The purpose of this indentation is to make each idea easy to see and also to show just how it is (7) to the ideas before and after it. No (8) is needed at the end of an idea unless it is written as a (9) sentence.Outlining, as a fairly comprehensive and effective method in language learning, certainly deserves our attention and (10) , particularly for advanced listeners.The blank form of an outline looks like this:I.A.B.1.a.b.2.C.II.A.1.2.B.C.10. The "Inverted Pyramid" in News ReportingBroadcasting news in English has some particular (1) , such as its style, its structure, the choice of words, and the logical order of presentation, etc.The standardized narrative (2) in news reporting is often called the "inverted pyramid". That is to say, the most important information is usually included in the news lead. And a news lead, in a sense, is also a condensed form of a complete news story. Each (3) sentence becomes less significant, providing further information on the “who”, “what”, “where”,“when” or …how”.If we want to sum up a certain news item, we can take words from either inside or outside the news stories. We can say, for example, “this news is about somebody‟s (4) onsomething”, or “it‟s about the (5)between country A and count ry B”.Other words such as (6) , remarks, attitudes, analysis can also be very useful.Apart from current news, radio reports on some breaking-throughs in science and technology also help update our knowledge about the world. However, vocabulary has proved to be a problem that often (7)our understanding of the new information. Therefore, in order to enhance our ability in listening, words that frequently appear in some popular science programs should be carefully studied. Besides, if we have a close examination of the (8) reports, we may find that they are often divided into different parts or paragraphs on the “(9) ”, the “test or experiment procedures”, the“observa ti ons”, the “findings or results” and so on. Thi s kind of knowledge also helps us in following the (10) developments in science.Key to Exercise 21. Focus on the Main Idea( 1 ) recognize ( 2 ) central ( 3 ) direction (4) inform ( 5 ) compare(6) stated (7) details (8) persuade (9) implied (10) hinted2. Don't Attempt to Write Too Much(1) complex (2) supporting (3) pace (4) reduce (5) minimum(6) appropriate (7)abbreviations (8)columns (9)sum (10)personal3. Be Careful with Numbers( 1 ) linked ( 2 ) broadcast ( 3 ) print ( 4 ) digit ( 5 ) losses(6) Intensive ( 7 ) presentations (8) commas (9) sensitivity (10) good4. How Is It Being Said -- Formal or Informal Language(1) chat (2) well-organized ( 3 ) structured (4) spontaneously(5) switches (6) complicated ( 7 ) extremes ( 8 ) background(9) judging (10) utterances5. Making Use of Them -- Signals and Fillers(1) missed ( 2 ) gesture ( 3 ) intonation (4) connect(5) length ( 6 ) need ( 7 ) gaps ( 8 ) embarrassing(9) recognize (10) essential6. Letting Things Go -- Speed and V ocabulary( 1 ) control (2) glance ( 3 ) fail (4) position( 5 ) clarification (6) barrier ( 7 ) determination ( 8 ) gap( 9 ) pass ( 10 ) incompleteness7. Thinking Ahead of the Speaker -- Anticipation Helps( 1 )communicative (2)matching (3)familiarity (4)knowledge( 5 ) pre-listening (6) related (7) orientated ( 8 ) readiness( 9 ) logical ( 10 ) utterance8. You Just Can't Remember So Much -- Learn to Select, Learn to Simplify( 1 ) frustrating ( 2 ) production ( 3 ) partial (4) inability( 5 ) goal ( 6 ) simplify ( 7 ) essential ( 8 ) grasp( 9 ) turning (10) smarter9. Represent the Ideas Clear and Clean -- Outlining( 1 ) classifying ( 2 ) scattered ( 3 ) symbols (4) decreasing ( 5 ) Lesser (6) equal ( 7 ) related ( 8 ) punctuation ( 9 ) complete ( 10 ) practice10. The "Inverted Pyramid" in News Reporting( 1 )characteristics (2)procedure (3)succeeding (4)view( 5 ) relationship ( 6 ) comments ( 7 ) hinders ( 8 ) experiment (9) subjects (10) latest。

Exercise表示练习是是可数还有两操是眼保健操光坡体操都是可数但表示锻炼运动时就是不可数以丑衬美美更美——名言因为一个是which ，一个是where 如：which city do you want to go to ？Where do you want to go ？where本身便可做地点状语，不需用介词加以修饰、而which指代人或物，是名词性质的疑问词、in which=where 就像for which=why 一样、less是在有比较的情况下运用的，可数或者不可数都可以用little不可数表示很少，几乎没有。

a little 是不可数是一些的意思。

a few 表示可数是一些的意思。

Few 表示可数是很少的，几乎没有的意思。

1、because 表示“由于，因为”，是连词，后接从句。

比如：She doesn't go to school because she is ill.2、because of 是介词，后接名词、代词、动词的ing形式，或者名词性从句。

比如：She doesn't go to school because of her illness.We should never look down upon a person because of what his parents have done.我们不应该因为一个人的父母所做的事而看不起他本人。

长征的历史事件血战湘江突破乌江四渡赤水巧渡金沙江强渡大渡河飞夺泸定桥包座战役激战腊子口直罗镇之战东征战役西征战役Advice 是不可数名词！物理响度与音调的差别？响度和音调对于初学的学生而言的却比较难。

人的认知经验和抽象的物理知识在学习响度和音调的时候产生了矛盾。

这样便使他们学习的时候很容易产生错误的理解。

响度看振幅即看声源的振动幅度，导致它振动幅度变化的重要的是看让声源振动的力的大小。

学生在理解的时候要注意区分这样意思的关键词。

Find the word or phrase from the list below that best matches the description in the following questions.1.1.1 Computer used to run large problems and usually accessed via a network ==> 3) servers1.1.2 10^15 or 2^50 bytes (i.e., 10 to the 15 or 2 to the 50) ==> 7) petabyte1.1.3 Computer composed of hundreds to thousands of processors and terabytesof memory ==> 5) supercomputers1.1.4 Today's science fiction application that probably will be available in nearfuture ==> 1) virtual worlds1.1.5 A kind of memory called random access memory==> 12) RAM1.1.6 Part of a computer called central processor unit ==> 13) CPU1.1.7 Thousands of processors forming a large cluster ==> 8) datacenters1.1.8 A microprocessor containing several processors in the same chip==> 10) multi-core processors1.1.9 Desktop computer without screen or keyboard usually accessed via a network==> 4) low-end servers1.1.10 Currently the largest class of computer (i.e., there are moreof these types of computers than any others) that runs one applicationor one set of related applications ==> 9) embedded computers1.1.11 Special language used to describe hardware components ==> 11) VHDL1.1.12 Personal computer delivering good performance to single users at lowcost ==> 2) desktop computers1.1.13 Program that translates statements in high-level language to assemblylanguage==> 15) compiler1.1.14 Program that translates symbolic instructions to binary instructions==> 21) assembler1.1.15 High-level language for business data processing ==> 25) cobol1.1.16 Binary language that the processor can understand==> 19) machine language1.1.17 Commands that the processors understand ==> 17) instruction1.1.18 High-level language for scientific computation ==> 26) fortran1.1.19 Symbolic representation of machine instructions ==> 18) assembly language1.1.20 Interface between user's program and hardware providing a variety ofservices and supervision functions ==> 14) operating system1.1.21 Software/programs developed by the users ==> 24) application software1.1.22 Binary digit (value 0 or 1) ==> 16) bit1.1.23 Software layer between the application software and the hardware thatincludes the operating system and the compilers ==> 23) system software1.1.24 High-level language used to write application and system software==> 20) C1.1.25 Portable language composed of words and algebraic expressions thatmust be translated into assembly language before run in a computer ==> 22) high-level language1.1.26 10^12 or 2^40 bytes==> 6) terabyteExercise 1.21.2.1 For a color display using 8 bits for each of the primary colors (red, green, blue) per pixel, what should be the minimum size in bytes of the frame buffer to store a frame?8 bits × 3 colors = 24 bits/pixel => 4 bytes/pixel.1280 × 800 pixels = 1,024,000 pixels.1,024,000 pixels × 4 bytes/pixel = 4,096,000 bytes (approxitly 4 Mbytes).1.2. 2 How many frames could it store, assuming the memory contains no other information?2 GB = 2000 MbytesNumber of frames = 2000 Mbytes/4 Mbytes = 500 frames1.2.3 If a 256 Kbytes file is sent through the Ethernet connection, how long it would take?1 gigabit network ==> 1 gigabit/per second = 125 Mbytes/second.File size: 256 Kbytes = 0.256 Mbytes.Time= Mbytes/network speed: 0.256/125 = 2.048 ms.Exercise 1.31.3.1 Which processor has the highest performance expressed in instructions per second?P2 has the highest performanceP1 (Performance = instructions/sec) = 2 × 10^9/1.5 = 1.33 × 10^9P2 (Performance = instructions/sec) = 1.5 × 10^9/1.0 = 1.5 × 10^9P3 (Performance = instructions/sec) = 3 × 10^9/2.5 = 1.2 × 10^91.3.2 If the processors each execute a program in 10 seconds, find the number of cycles and the number of instructions.Number of cycles = time × clock rateCycles (P1) = 10 × (2 × 10^9) = 20 × 10^9 sCycles (P2) = 10 × (1.5 × 10^9) = 15 × 10^9 sCycles (P3) = 10 × (3 × 10^9) = 30 × 10^9 sTime = (Number of instructions × CPI)/clock rate; Number of instructions = Number of cycles/CPI Instructions (P1) = 20 × 10^9/1.5 = 13.33 × 10^9Instructions (P2) = 15 × 10^9/1 = 15 × 10^9Instructions (P3) = 30 × 10^9/2.5 = 12 × 10^91.3.3 We are trying to reduce the time by 30% but this leads to an increase of 20% in the CPI. What clock rate should we have to get this time reduction?Time new = Time old × 0.7 = 7 sCPI new = CPI old × 1.2 => CPI (P1) = 1.8, CPI (P2) = 1.2, CPI (P3) = 3Time = Number of instructions × CPI/clock rateTime (P1) = 13.33 × 10^9 × 1.8/7 = 3.42 GHzTime (P2) = 15 × 10^9 × 1.2/7 = 2.57 GHzTime (P3) = 12 × 10^9 × 3/7 = 5.14 GHz1.3.4 Find the IPC (instructions per cycle) for each processor.IPC new = 1/CPI old = Number of instructions/ (time × clock rate)IPC (P1) = (20 x 10^9)/(7 x 3) = 1.42IPC (P2) = (30 x 10^9)/(10 x 2.5) = 2IPC (P3) = (90 x 10^9)/(9 x 4) = 3.331.3.5 Find the clock rate for P2 that reduces its execution time to that of P1.Time new/Time old = 7/10 = 0.7.Clock rate new = Clock rate old/0.7 = 1.5 GHz/0.7 = 2.14 GHz1.3.6 Find the number of instructions for P2 that reduces its execution time to that of P3.Time new/Time old = 9/10 = 0.9.Instructions new = Instructions old × 0.9 = (30 × 10^9)× 0.9 = 27 × 10^9Exercise 1.41.4.1 Given a program with 106 instructions divided into classes as follows: 10% class A, 20% class B, 50% class C and 20% class D, which implementation is faster?P2 has a faster implementation timeClass A: 10^5 instr.Class B: 2 × 10^5 instr.Class C: 5 × 10^5 instr.Class D: 2 × 10^5 instr.Time = Number of instructions × CPI/clock rateP1: Time class A = 0.66 × 10^−4Time class B = 2.66 × 10^−4Time class C = 10 × 10^−4Time class D = 5.33 × 10^−4Total time P1 = 18.65 × 10^−4P2: Time class A = 10^−4Time class B = 2 × 10^−4Time class C = 5 × 10^−4Time class D = 3 × 10^−4Total time P2 = 11 × 10^−41.4.2 What is the global (i.e., average) CPI for each implementation?CPI = time × clock rate/ number of instructionsCPI (P1) = (18.65 × 10^−4) × (1.5 × 10^9)/10^6= 2.79CPI (P2) = (11 × 10^−4) × (2 × 10^9)/10^6 = 2.21.4.3 Find the clock cycles required in both cases.Clock cycles (P1) = (10^5 × 1) + ((2 × 10^5) × 2) + ((5 × 10^5) × 3) + ((2 × 10^5) × 4) = 28 × 10^5Clock cycles (P2) = (10^5 × 2) + ((2 × 10^5) × 2) + ((5 × 10^5) × 2) + ((2 × 10^5) × 3) = 22 × 10^51.4.4 Assuming that arithmetic instructions take 1 cycle, load and store 5 cycles and branch 2 cycles, what is the execution time of the program in a 2 GHz processor?(500 × 1) + (50 × 5) + (100 × 5) + (50 × 2) × (0.5 × 10^–9) = 675 ns1.4.5 Find the CPI for the program.CPI = time × clock rate/ Number of instructionsCPI = ((675 × 10^–9) × (2 × 10^9))/700 = 1.921.4.6 If the number of load instructions can be reduced by one-half, what is the speed-up and the CPI?Time = ((500 × 1) + (50 × 5) + (50 × 5) + (50 × 2)) × (0.5 × 10^–9) = 550 nsSpeed-up = 675 ns/550 ns = 1.22CPI = ((550 × 10^–9) × (2 × 10^9))/700 = 1.57Exercise 1.51.5.1 Assume that peak performance is defined as the fastest rate that a computer can execute any instruction sequence. What are the peak performances of P1 and P2 expressed in instructions per second?1.5.2 If the number of instructions executed in a certain program is divided equally among the classes of instructions except for class A, which occurs twice as often as each of the others. Which computer is faster? How much faster is it?1.5.3 If the number of instructions executed in a certain program is divided equally among the classes of instructions except for class E, which occurs twice as often as each of the others? Which computer is faster? How much faster is it?1.5.4 Assuming that computes take 1 cycle, loads and store instructions take 10 cycles, and branches take 3 cycles, find the execution time of the program on a 3 GHz MIPS processor.1.5.6 Assuming that computes take 1 cycle, loads and store instructions take 2 cycles, and branches take 3 cycles, what is the speed-up of a program if the number of compute instruction can be reduced byone-half?Exercise 1.61.6.1 For the same program, two different compilers are used. The table above shows the execution time of the compiled program. Find the average CPI for the program given that the processor has a clock cycle time of 1 nS.1.6.2 Assume the average CPI found in 1.6.1, but that the compiled program runs on two difference processors. If the execution times on the two processors are the same, how much faster is the clock of the processor running compiler A’s code versus the clock of the processor running compiler B’s code?1.6.3 A new compiler is developed that uses only 600 million instructions and has an average CPI of 1.1. What is the speed-up of using this new compiler versus using Compiler A or B on the original processorof 1.6.1?1.6.4 Assume that peak performance is defined as the fastest rate that a computer can execute any instruction sequence. What is the peak performance of P1 and P2 expressed in instructions per second?1.6.5 If the number of instructions executed in a certain program is divided equally among the classes of instructions in Problem2.36.4 except for class A, which occurs twice as often as each of the others, how much faster is P2 than P1?1.6.6 At what frequency does P2 have the same performance as P1 for the instruction mix given in 1.6.5? Exercise 1.71.7.1 What is the geometric mean of the ratios between consecutive generations for both clock rate and power? (The geometric mean is described in Section 1.7.)Geometric mean clock rate ratio = (1.28 × 1.56 × 2.64 × 3.03 × 10.00 × 1.80 × 0.74)1/7 = 2.15Geometric mean power ratio = (1.24 × 1.20 × 2.06 × 2.88 × 2.59 × 1.37 × 0.92)1/7 = 1.621.7.2 What is the largest relative change in clock rate and power between generations?Largest clock rate ratio = 2000 MHz/200 MHz = 10Largest power ratio = 29.1 W/10.1 W = 2.881.7.3 How much larger is the clock rate and power of the last generation with respect to the first generation?Clock rate: 2.667 × 10^9/12.5 × 106 = 212.8Power: 95 W/3.3 W = 28.781.7.4 Find the average capacitive loads, assuming a negligible static power consumption.Capacitive = Power/Voltage^2 × clock rate80286: C = 0.0105 × 10^−680386: C = 0.01025 × 10^−680486: C = 0.00784 × 10^−6Pentium: C = 0.00612 × 10^−6Pentium Pro: C = 0.0133 × 10^−6Pentium 4 Willamette: C = 0.0122 × 10^−6Pentium 4 Prescott: C = 0.00183 × 10^−6Core 2: C = 0.0294 × 10^−61.7.5 Find the largest relative change in voltage between generations.Pentium Pro/Pentium 4 Willamette = 3.3/1.75 = 1.781.7.6 Find the geon1etric mean of the voltage ratios in the generations since the Pentium.Pentium Pro / Pentium => 3.3/5 = 0.66Pentium 4 Willamette/ Pentium Pro => 1.75/3.3 = 0.53Pentium 4 Prescott / Pentium 4 Willamette => 1.25/1.75 = 0.71Core 2 / Pentium 4 Prescott => 1.1/1.25 = 0.88Geometric mean = 0.68Exercise 1.81.8.1 How much has the capacitive load been reduced between versions if the dynamic power has been reduced by 10%?Power1 = V^2× clock rate × Capacitive; Power2 = 0.9 Power1C2/C1 = 0.9 × 5^2 × 0.5 × 10^9/3.3^2 × 1 × 10^9 = 1.031.8.2 By how much has the dynan1ic power been reduced if the capacitive load does not change?Power2/Power1 = V22 × clock rate2/V12 × clock rate1Power2/Power1 = 0.87 => Reduction of 13%1.8.3 Assuming that the capacitive load of version 2 is 80% the capacitive load of version 1, find the voltage for version 2 if the dynamic power of version 2 is reduced by 40% from version 1.Power2 = V22 × 1 × 10^9 × 0.8 × C1 = 0.6 × Power1Power1 = 52 × 0.5 × 10^9 × C1V22 × 1 × 10^9 × 0.8 × C1 = 0.6 × 52 × 0.5 × 10^9 × C1V2 = ((0.6 × 52 × 0.5 × 10^9)/(1 × 10^9 × 0.8))1/2 = 3.06 V1.8.4 By what factor does the dynamic power scales?Power new = 1 × C old × V2old/(2−1/4)2× clock rate × 21/2 = Power oldAccording to this the power scales by 1.1.8.5 Find the scaling of the capacitance per unit area.1/2−1/2 = 21/21.8.6 Using data from Exercise 1.7, find the voltage and clock rate of the Core 2 processor for the next process generation.Voltage = 1.1 × 1/2−1/4 = 0.92 VClock rate = 2.667 × 21/2 = 3.771 GHzExercise 1.91.9.1 Find the percentage of the total dissipated power comprised by static power.1.9.2 If the total dissipated power is reduced by 10% while maintaining the static to total power rate of problem 1.9.1, how much should the voltage be reduced to maintain the same leakage current?1.9.3 Determine the ratio of static power to dynamic power for each technology.1.9.4 Determine the static power for each version at 0.8 V, assuming a static to dynamic power ratio of 0.6.Power st/Power dyn = 0.6 => Power st = 0.6 × Power dyna)Power st = 0.6 × 35 W = 21 Wb)Power st = 0.6 × 30 W = 18 W1.9.5 Determine the static power and dynamic power dissipation assuming the rates obtained in problem 1.9.1.L lk = Voltage / Power sta) I lk = 21/0.8 = 26.25 Ab) I lk = 18/0.8 = 22.5 AExercise 1.101.10.1 The table above shows the number of instructions required per processor to complete a program on a multiprocessor with 1, 2, 4, or 8 processors. What is the total number of instructions executed per processor? What is the aggregate number of instructions executed across all processors?Instructions per processor = (Arith Inst x Arith Cpi)+( load Inst x load Cpi)+( branch Inst x branch Cpi)program on I, 2, 4, and 8 processors. Assume that each processor has a 2 GHz clock frequency.1.10.3 If the CPI of arithmetic instructions was doubled, what would the impact be on the execution time of the program on 1,2,4, or 8 processors?1.10.4 Assuming a 3 GHz clock frequency, what is the execution time of the program using 1, 2, 4, or 8 cores.1.10.5 Assuming that the power consumption of a processor core can be described by the following equation:Power = (5.0n1A)/(MHz)* Voltage^2Where the operation voltage of the processor is described by the following equation:Voltage = 1/5*Frequency+0.4With the frequency measured in GHz. So, at 5 GHz, the voltage would be 1.4V. Find the power consumption ofthe program executing on 1, 2, 4, and 8 cores assuming that each core is operating at a 3GHz clock frequency. Likewise, find the power consumption of the program executing on I, 2, 4, or 8 cores assuming that each core is operating at 500 MHz.Exercise 1.111.11.1 Find the yield.Wafer area = π × (d/2)2a. Wafer area = π × 7.52 = 176.7 cm2b. Wafer area = π × 12.52 = 490.9 cm2Die area = wafer area/dies per wafera. Die area = 176.7/90 = 1.96 cm2b. Die area = 490.9/140 = 3.51 cm2Yield = 1/ (1 + (defect per area × die area)/2)2a. Yield = 0.97b. Yield = 0.921.11.2 Find the cost per die.Cost per die = cost per wafer/ (dies per wafer × yield)a. Cost per die = 0.12b. Cost per die = 0.161.11.3 If the number of dies per wafer is increased by 100/0 and the defects per area unit increases by 150/0, find the die area and yield.a. Dies per wafer = 1.1 × 90 = 99Defects per area = 1.15 × 0.018 = 0.021 defects/cm2Die area = wafer area/Dies per wafer = 176.7/99 = 1.78 cm2Yield = 0.97b. Dies per wafer = 1.1 × 140 = 154Defects per area = 1.15 × 0.024 = 0.028 defects/cm2Die area = wafer area/Dies per wafer = 490.9/154 = 3.19 cm2Yield = 0.931.11.4 Find the defects per area unit for each technology given a die area of 200 mm2Yield = 1/(1 + (defect per area × die area)/2)2Defect per area = (2/die area) (y−1/2− 1)Replacing values for T1 and T2 we getT1: defects per area = 0.00085 defects/mm2 = 0.085 defects/cm2T2: defects per area = 0.00060 defects/mm2 = 0.060 defects/cm2T3: defects per area = 0.00043 defects/mm2 = 0.043 defects/cm2T4: defects per area = 0.00026 defects/mm2 = 0.026 defects/cm2Exercise 1.121.12.1 Find the CPI if the clock cycle time is 0.333 ns.CPI = clock rate × CPU time/instr. countClock rate = 1/cycle time = 3 GHza. CPI (pearl) = 3 × 10^9 × 500/2118 × 10^9 = 0.7b. CPI (mcf) = 3 × 10^9 × 1200/336 × 10^9 = 10.71.12.2 Find the SPEC ratio.SPECratio = ref. time/execution time.a. SPECratio (pearl) = 9770/500 = 19.54b. SPECratio (mcf) = 9120/1200 = 7.61.12.3 For these two benchmarks, find the geometric mean.(19.54 × 7.6)1/2 = 12.191.12.4 Find the increase in CPU time if the number of instruction of the benchmark is increased by 100/0 without affecting the CPI.CPU time = number of instructions × CPI/clock rateIf CPI and clock rate do not change, then the CPU time will increase equal to the number ofinstructions, which would be by 10%.1.12.5 Find the increase in CPU time if the number of instruction of the benchmark is increased by 10% and the CPI is increased by 5%.CPU time (before) = number of instructions × CPI/clock rateCPU time (after) = 1.1 × number of instructions × 1.05 × CPI/clock rateCPU times (after)/CPU time (before) = 1.1 × 1.05 = 1.155.CPU time is increased by 15.5%1.12.6 Find the change in the SPECratio for the change described in 1.12.5.SPECratio = reference time/CPU timeSPECratio (after)/SPECratio (before) = CPU time (before)/CPU time (after) = 1/1.1555 = 0.86The SPECratio is decreased by 14%.Exercise 1.131.13.1 Find the new CPI.CPI = (CPU × clock rate)/Number of instr.a. CPI = 450 × 4 × 10^9/ (0.85 × 2118 × 10^9) = 0.99b. CPI = 1150 × 4 × 10^9/ (0.85 × 336 × 10^9) = 16.101.13.2 In general, these CPI values are larger than those obtained in previous exercises for the same benchmarks. This is due mainly to the clock rate used in both cases, 3 GHz and 4 GHz. Determine whether the increase in the CPI is similar to that of the clock rate. If they are dissimilar, why?Clock rate ratio = 4 GHz/3 GHz = 1.33.a. CPI at 4 GHz = 0.99, CPI at 3 GHz = 0.7, ratio = 1.41b. CPI at 4 GHz = 16.1, CPI at 3 GHz = 10.7, ratio = 1.50They are different because the CPU time has been reduced by a lower percentage, even though the number of instructions has been reduced by 15%,1.13.3 How much has the CPU time been reduced?a. 450/500 = 0.90CPU time reduction = 10%b. 1150/1200 = 0.958CPU time reduction = 4.2%1.13.4 If the execution time is reduced by an additional 10% without affecting the CPI and with a clock rate of 4 GHz, determine the number of instructions.Number of instructions = CPU × clock rate/CPI.a. Number of instructions = 820 × 0.9 × 4 × 10^9/0.96 = 3075 × 10^9b. Number of instructions = 580 × 0.9 × 4 × 10^9/2.94 = 710 × 10^91.13.5 Determine the clock rate required to give a further 10% reduction in CPU time while maintaining the nun1ber of instructions and CPI unchanged.Clock rate = Number of instructions × CPI/CPU time.Clock rate new = Number of instructions × CPI/0.9 × CPU time = 1/0.9 clock rate old = 3.33 GHz.1.13.6 Determine the clock rate if the CPI is reduced by 15% and the CPU time by 20% while the number of instructions is unchanged.Clock rate = Number of instructions × CPI/CPU time.Clock rate new = Number of instructions × 0.85 × CPI/0.80 CPU time = 0.85/0.80 clock rate old = 3.18 GHz. Exercise 1.141.14.1 One usual fallacy is to consider the computer with the largest clock rate as having the large perfonl1ance. Check if this is true for PI and P2.Number of instructions = 106Tcpu (P1) = 106 × 1.25/4 × 10^9 = 0.315 × 10–3 sTcpu (P2) = 106 × 0.75/3 × 10^9 = 0.25 × 10–3 sClock rate (P1) > clock rate (P2), but performance (P1) < performance (P2)1.14.2 Another fallacy is to consider that the processor executing the largest number of instruction will need a larger CPU time. Considering that processor PI is executing a sequence of 106 instructions and that the CPI of processors PI and P2 do not change, detenl1ine the number of instructions that P2 can execute in the same time that PI needs to execute 106 instructions.P1: 106 instructions, Tcpu (P1) = 0.315 × 10–3 sP2: Tcpu (P2) = N × 0.75/3 × 109N = 1.26 × 1061.14.3 A common fallacy is to use MIPS (millions of instructions per second) to con1pare the performance of two different processors, and consider that the processor with the largest MIPS has the largest perforn1ance. Check if this is true for PI and P2.MIPS = Clock rate × 10−6 /CPIMIPS (P1) = 4 × 10^9 × 10–6/1.25 = 3200MIPS (P2) = 3 × 10^9 × 10–6/0.75 = 4000MIPS (P1) < MIPS (P2), performance (P1) < performance (P2) in this caseAnother common performance figure is MFLOPS (millions of floating-point operations per second), defined asMFLOPS = Number of FP operations/(execution time x 10^6)1.14.4 Find the MFLOPS figures for the programs.a. FP op = 106 × 0.4 = 4 × 105, clock cylesfp = CPI × Number of FP instr. = 4 × 105Tfp = 4 × 105 × 0.33 × 10–9 = 1.32 × 10–4 then MFLOPS = 3.03 × 103b. FP op = 3 × 106 × 0.4 = 1.2 × 106, clock cylesfp = CPI × Number of FP instr. = 0.70 × 1.2 × 106Tfp = 0.84 × 106 × 0.33 × 10–9 = 2.77 × 10–4 then MFLOPS = 4.33 × 1031.14.5 Find the MIPS figures for the programs.5 CPU clock cycles = FP cycles + CPI (L/S) × Number of instr. (L/S) + CPI (Branch) ×Number of instr. (Branch)a. 5 × 105 L/S instr., 4 × 105 FP instr. and 105 Branch instr.CPU clock cycles = 4 × 105 + 0.75 × 5 × 105 + 1.5 × 105 = 9.25 × 105Tcpu = 9.25 × 105 × 0.33 × 10–9 = 3.05 × 10–4MIPS = 106/ (3.05 × 10–4 × 106) = 3.2 × 103b. 1.2 × 106 L/S instr., 1.2 × 106 FP instr. and 0.6 × 106 Branch instr.CPU clock cycles = 0.84 × 106 + 1.25 × 1.2 × 106 + 1.25 × 0.6 × 106 = 3.09 × 106Tcpu = 3.09 × 106 × 0.33 × 10–9 = 1.01 × 10–3MIPS = 3 × 106/ (1.01 × 10–3 × 106) = 2.97 × 1031.14.6 Find the performance for the programs and con1pare with MIPS and MFLOPS.a. Performance = 1/Tcpu = 3.2 × 103b. Performance = 1/Tcpu = 9.9 × 102The second program has the higher performance, but the first program has the higher MIPSfigure.Exercise 1.151.15.1 By how much is the total time reduced if the time for FP operations is reduced by 20%?a. T fp = 35 × 0.8 = 28 s; T p1 = 28 + 85 + 50 + 30 = 193 s; Reduction of 3.5%b. T fp = 50 × 0.8 = 40 s; T p4 = 40 + 80 + 50 + 30 = 200 s; Reduction of 4.7%1.15.3 Can the total time be reduced by 20% by reducing only the time for branch instructions?a. T p1 = 200 × 0.8 = 160 s; T fp + T int + T l/s = 170 s. No the total time cannot be reduced by 20%b. T p4 = 210 × 0.8 = 168 s; T fp + T int + T l/s = 180 s. No the total time cannot be reduced by 20% Assume that each processor has a 2 GHz clock rate.1.15.4 By how much must we improve the CPI of FP instructions if we want the program to run two times faster?Clock cyles = CPI fp × Number of FP instr. + CPI int × Number of INT instr. + CPI l/s × Number of L/Sinstr. + CPIbranch × Number of branch instr.Tcpu = clock cycles/clock rate = clock cycles/2 × 109a. 1 processor=> clock cycles = 8192; T cpu = 4.096 sb. 8 processors=> clock cycles = 1024; T cpu = 0.512 sTo half the number of clock cycles by improving the CPI of FP instructions:CPI improved fp × Number of FP instr. + CPI int × Number of INT instr. + CPI l/s × Number of L/S instr. + CPI branch × Number of branch instr. = clock cycles/2CPI improved fp= (clock cycles/2 − (CPI int × Number of INT instr. + CPI l/s × Number of L/S instr. +CPI branch × Number of branch instr.))/Number of FP instr.a. 1 processor: CPI improved fp = (4096 – 7632)/560 => not possibleb. 8 processors: CPI improved fp = (512 – 944)/80 => not possible1.15.5 By how much must we improve the CPI of L/S instructions if we want the program to run two times faster?Using clock cycle from 1.15.4:To half the number of clock cycles improving the CPI of L/S instructions:CPI fp × Number of FP instr. + CP Iint × Number of INT instr. + CP Iimproved l/s × Number of L/S instr. +CPI branch × Number of branch instr. = clock cycles/2CPI improved l/s = (clock cycles/2 − (CPIfp × Number of FP instr. + CPI int × Number of INT instr. +CPI branch × Number of branch instr.))/Number of L/S instr.a. 1 processor: CPI improved l/s = (4096 – 3072)/1280 = 0.8b. 8 processors: CPI improved l/s = (512 – 384)/160 = 0.81.15.6 By how much is the execution time of the program improved if the CPI of INT and FP instruction is reduced by 40% and the CPI of L/S and branch is reduced by 30%?Clock cyles = CPIfp× Number of FP instr. + CPI int× Number of INT instr. + CPI l/s× Number of L/S instr. +CPI branch × Number of branch instr.T cpu = clock cycles/clock rate = clock cycles/2 × 109CPI int = 0.6 × 1 = 0.6; CPI fp = 0.6 × 1 = 0.6; CPI l/s = 0.7 × 4 = 2.8; CPI branch = 0.7 × 2 = 1.4a. 1 processor => T cpu (before improved) = 4.096 s; T cpu (after improved) = 2.739 sb. 8 processors =>T cpu (before improved) = 0.512 s; T cpu (after improved) = 0.342 s。

exercise是可数名词还是不可数名
exercise指“锻炼”时，是不可数名词；表示“体操”或“练习”时是可数名词，要用复数形式。

扩展资料
exercise和exercises的区别
exercise为不可数名词时：
1.（身体或脑力的）活动，锻炼，运动。

例如：to take exercise 锻炼；gentle exercise 平和的运动；
2.行使，运用，使用。

例如：the exercise of power by the government 政府权力的.行使；the exercise of discretion 自行决定权的行使。

exercises为可数名词时：
1.（保持健康或培养技能的）一套动作，训练活动，练习。

例如：breathing exercises 呼吸运动；exercises for the piano 钢琴练习；
2.习题，练习。

例如：grammar exercises 语法练习；do exercises 做习题。

exercise基本含义
n.(身体或脑力的)活动，锻炼，运动;(保持健康或培养技能的)一套动作，训练活动;习题;练习
v.行使;使用;运用;锻炼;训练;操练;锻炼(身体某部位)
第三人称单数：exercises
复数：exercises
现在分词：exercising
过去式：exercised
过去分词：exercised。

Exercise1翻译Exercise 11.In American high schools, some of the third graders have got into theevil habit of taking doses of uppers and downers.在美国，一些中学三年级的学生染上了吸食兴奋剂和镇静剂的恶习。

2.The president often considered economy in the White House kitchen.总统常常考虑在白宫的膳食方面如何减少开支。

3.Under capitalism drug and alcohol are used by some as escapemechanism.在资本主义社会，毒品和酒精有时被当作逃避现实的工具。

4.Next dreadful thing to battle lost is a battle won.战败最惨，而战胜次之。

5.She is a lady of blue blood.她出身高贵。

6.You can’t have your cake and eat it too.两者不可兼得（鱼与熊掌不可兼得）。

7.Let’s sleep on it.让我们暂且把问题搁一下。

8.As one of the Four Tigers in Asia, Hong Kong is also known as theOriental Pearl and the Shopping Paradise.作为亚洲四小龙之一，香港同样也以东方明珠和购物天堂而闻名。

9.There are cattle in the fields, but we sit down to beef.牧场上放的是牛，餐桌上吃的是牛肉。

10.If children are accorded the respect as adults, they can becounted onto display comparable manners.如果孩子能够像同成年人一样得到尊重，他们同样也会对人彬彬有礼。

exercise的用法单复数一、exercise的用法1. 单数形式在英语中，exercise是一个可数名词，单数形式为"exercise"。

它指的是一种体育活动或锻炼身体的方式。

例如：- Regular exercise is important for maintaining good health.（定期锻炼对于保持身体健康很重要。

）2. 复数形式exercise的复数形式是exercises。

当我们想表达多个体育活动或锻炼方式时，可以使用复数形式。

例如：- There are various exercises you can do to stay fit, such as jogging, swimming, and cycling.（有很多种你可以做来保持健康的锻炼方式，比如慢跑、游泳和骑自行车等。

）二、不同上下文中的 exercise 用法1. 动词用法除了作为名词外，exercise还可以作为动词使用，意思是“锻炼身体”或“使行使”。

例如：- She exercises for an hour every day to keep fit.（她每天锻炼一个小时以保持身材健美。

）- The professor asked the students to exercise caution while conducting the experiment.（教授要求学生们在进行实验时小心谨慎。

）2. 专业领域中的用法在某些专业领域中，exercise还具有特殊含义。

2.1 医学领域在医学领域，exercise 可以表示“活动”或“功能性训练”。

例如：- Physical exercise is an important factor in the prevention of heart disease.（体育锻炼是预防心脏病的重要因素。

）2.2 语言学习中在语言学习中，exercise指的是一种练习材料，用于巩固和应用所学的知识。

英语听说课教学设计〔共4篇〕第1篇：高中英语听说课教学设计必修五unit3 life in the future听说课教学设计教学目的：通过听一段对话，对大意有整体印象，并能获得局部细节信息。

教学重点：听对话时，既要注意大意，又要注意细节。

通过练习，训练学生的根本语言技能。

教学方法：work 教具准备：多媒体教学流程：第一步：作业检查及引入话题〔分组辩论〕1.Ask Ss to have a debate on whether people can live on Mars.2.Teacher gives ments on bothsides,saying : both of you have given sound reasons to support your arguments.And now let’s listen to an interview between Li Qiang and Walker Hiller, who is to build a town on Mars.第二步：听力训练〔一〕〔双人活动〕 Listening and speaking(page23) 1.Get the Ss to get through Exercise1.2.First, listen for the Ss to finish Exercise1 3.Second,listen for the Ss to finish Exercise2 4.Third,listen for the Ss to put down thequestion in it that are used to make predictions.Can you imagine how that’ll be ach ieved Is it likely that you can find and use water I wonder if...How health will the people be, I wonder 5.Get the Ss to exchange their information to correct their answers 第三步：口语活动1.〔pair work〕Ask Ss to list some questions about what life will be like in you hometown in 1000 years’ time, using the expreions above to help them.2.(pair work) Interview Situation : Suppose you’re in anewly-elected major, and now is being interviewed on TV.The host is raising some questions on your plan for the ing five years.Have the Ss to make up theinterview in pairs, trying to use the expreions above.第四步：听力训练〔二〕〔双人活动〕Listening task(page55) 1.Ss read the phrases before listening to the tape.2.Listen to the tape and finish Exercise1 第五步：口语训练〔二〕广告词设计大赛1.Ask the Ss to have a look at the requirements in the “taking part”2.Let them choose of the three as they like and work in groups of four and design thetext of an ad for the product.3.Ask Ss to read their texts to the cla, and Ss vote for theirfavorite.4.Count the result to see which group get the most votes.5.Teacher may give an award to the winners.第六步：布置作业Ask the Ss to go over what they learned in the cla according to the “Summing up” on page 24.教学反思：这一节听说课的教学设计，从听前的问题预测，到听后的问题答复，都与利于学生的听力培养和口语表达，是学生在听说过程中逐步进步英语运用才能。

［教材习题研讨］方法点拨INTRODUCTION[P3] Exercise 21.architect2.locatendmark4.writer5.gallery6.scuplture7.ancient[P3] Exercise 31.Paris，Athens2.Barcelona3.Paris4.Paris，Florence，Athens5.Athens[P3] Exercise 4True：1. 2. 5.7.False：3. 4. 6.8.FUNCTION[P4] Exercise 21.on2.across3.between4.on5.off[P4] Exercise 41.between2.north3.south4.between5.westGRAMMAR[P5] Exercise 21.Florence is visited by a million tourists each year.2.London was visited by ten million people last year.3.The Mona Lisa was painted by Leonardo da Vinci.4.The Mona Lisa wasn’t painted by Picasso.5.The Great Wall of China was built by thousands of workers.[P5] Exercise 31.No，it isn’t.It is located in Paris.2.No，it isn’t.It is situated on the River Seine.3.No，it isn’t.It is visited by a million tourists on every year.4.No，it isn’t.Athens is known as the birthplace of Western civilization.5.No，it wasn’t.It was built 2400 years ago.GRAMMAR[P7] Exercise 21.are playing2.are having3.lives，live[P7] Exercise 41.Neither Amy nor Helen can speak Chinese. 辨析词义，准确理解单词，并注意记忆积累，尤其是一个同义的“人”和“语言”形式上的区别。

ExerciseStatics of the Ship响砂山月牙泉第一章复习思考题1．船舶静力学研究哪些内容？2．在船舶静力学计算中，坐标系统是怎样选取的？3．作图说明船体的主尺度是怎样定义的？其尺度比的主要物理意义如何？4．作图说明船形系数是怎样定义的？其物理意义如何？试举一例说明其间的关系。

5．对船体近似计算方法有何要求？试说明船舶静力学计算中常用的近似计算法有哪几种？其基本原理、适用范围以及它们的优缺点。

复习思考题6．提高数值积分精确度的办法有哪些？并作图说明梯形法、辛浦生法对曲线端点曲率变化较大时如何处理？以求面积为例，写出其数值积分公式。

7．分别写出按梯形法，辛浦拉法计算水线面面积的积分公式，以及它们的数值积分公式和表格计算方法。

(5,8,-1) 法、(3,10,-1)法的适用范围。

8．写出计算水线面面积的漂心位置和水线面面积对x轴y轴的惯性矩的积分公式。

并应用求面积的原理写出其数值积分公式和表格计算方法。

复习思考题9．如何应用乞贝雪夫法？试以九个乞贝雪夫坐标，写出求船舶排水体积的具体步骤。

10．说明积分曲线、重积分曲线与原曲线的关系．并以水线面面积曲线为例说明积分曲线、重积分曲线的应用。

Exercise 1-1已知: L=155m,B=18m,d=7.1m,V=10900m3,Am=115m2,Aw=1980m2求：Cb=V/LBd=10900/(155*18*7.1)=0.550Cp=V/Lam=10900/(155*115)=0.62Cw=Aw/BL=19800/(18*155)=0.710Cm=Am/Bd=115/(18*7.1)=0.900Cvp=V/Awd=10900/(1980*7.1)=0.775某海洋客船L=155m，B=18m，d=7.1m，V=10900m3，Am=115m2，Aw=1980m2。

试求Cb, Cp, Cw, Cm, Cvp。

Exercise 1-2两相等的正圆锥体在底部处相连接，每个锥体的高等于其底部直径．这个组合体浮于水面，使其两个顶点在水表面上，试绘图并计算：（1）中横剖面系数Cm，（2）纵向棱形系数Cp，（3）水线面系数Cw，（4）方形系数Cb。