LWTE 1B Chapter 1 Choosing a Pet 1 (2)

SIDE BY SIDE I CHPATER 16 测验卷一写出下列词组的中文或英文（15%）1 take a shower _________________2 do exercise _________________3 drive to the supermarket ________________4 see a movie_________________5 go to sleep _________________6 on the way to work_________________7 take the subway _________________8 brush one’s teeth _________________9 miss the bus _________________ 10 leave for work _________________11 上班迟到_________________ 12 生气_________________13 等火车_________________ 14 写信_________________15 吃早饭_________________二辨音，找出下列四个单词中划线部分不同发音的单词(10%)（） 1 A wrote B drove C forgot D stole( ) 2 A exercise Bgrocery C breakfast D letter( ) 3A though B bought C caught D thought( ) 4 A bicycle B briefcase C headache D clean( ) 5 A stayed B listened C missed Denjoyed三配对(20%)（）1 Did you brush your teeth last night?（）2 What did they do last night?（）3 I see.（）4 When did you leave for work this morning?（）5 Why were you late for work today?（）6 Did your children make dinner yesterday?（）7 I didn’t go to the library last week.（）8 How did he go to the station?（）9 Did Timothy do his exercises yesterday afternoon?（）10 Did she see a movie with her friends last Sunday?A No, they didn’t. I made dinner yesterday.B I didn’t ,either.C No, I didn’t.D He went there on foot.E No,he didn’t. He listened to music.F They did their homework.G I missed the train.H Yes, she did.I I left at about 7:00 A.M.J I’m sorry I’m late. I got up late this morning.四写出下列动词的过去式(10%)1 get _________________2 take _________________3 have _________________4 buy _________________5 make _________________6 write_________________7 read _________________ 8 see_________________9 forget _________________ 10 meet _________________五动词填空(20%)1 Victor usually __________ (get) up at 7 A.M.,but he _________________(not get)up at 7 A.M. yesterday morning.2 We _________________(go)to the library and _________________（read）some interesting books last Saturday.3 Bob _________________(forget) his backpack and _________________(have)to go back home to get it.4 --_________________Michael _________________(buy)a car a month ago?—No. He _________________(buy) a bicycle.5When _________________he _________________(write)this letter?He _________________(write)it just now.六改写句子（15%）1 Jennifer did her exercises two hours ago.(改为否定句)2 We rode our bicycles to school this morning .(改为否定句)3 Wanda had a headache yesterday evening.(改为一般疑问句)4 Bob read the newspaper just now.(改为一般疑问句)5 My mother bought some groceries at the supermarket last week.(根据划线部分提问)七写作Tell about a day off you enjoyed.(10%)What did you do in the morning?In the afternoon?In the evening?_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________。

可编辑修改精选全文完整版Unit2 Precision farming hits its target When we think of farming, the first image that springs to mind might be of a farmer working in a field under the 1._________ (bake) sun. Face covered in sweat, he might be walking through the field, carefully checking his crops before deciding what needs to be done. In modern times, however, this deep-rooted image of a traditional farmer is being changed. The collaboration between farming and technology has given rise 2._______ precision farming, an approach that equips farmers with the tools and data they need to make 3. _______(rely) decisions with remarkable accuracy. This evolution is having a positive impact on farming, while also providing better solutions to the world's pressing food problems.It is the advent of modern technology that has turned farming into a 4. _______ (high) precise industry. This latest wave of innovation offers farmers information that is more detailed, measurements that are more accurate and solutions that are more effective. Therefore, precision farming is a data-driven approach to the improvement of food production with the primary goals of reducing a farm's input, increasing its output and better conserving the environment. These goals can be achieved with a 5. ________ (combine) of information-gathering tools like sensors, satellites and drones, and advanced technologies such as artificial intelligence(Al). With 6._______ (mass) amounts of data on the state of their farmland 7. _______ (gather), analysed and processed in real time, farmers are able to give the best possible care to the crops that most need it at the most appropriate time and put their resources to the best use. As an added bonus, the decline in the amount of unnecessary chemicals 8. ________ (minimum) potential threats to the environment.Precision farming boasts a diverse range of application 9. _________ (capable) at different stages of food production-monitoring, diagnosing, identifying and targeting. Soil sampling, an example of precision farming in its most fundamentalform, provides an accurate means for farmers to tend their crops. Field sensors check the soil's moisture, nutrient levels and pH levels, 10. _________ (enable) farmers to monitor their crops at any time, from anywhere. As the data library builds 11._______, "a big picture" of the soil is revealed so that farmers are able to accurately assess the condition of the soil in real time, identify potential problems and work out solutions accordingly. For instance, if the soil is found to be poor in nutrients, not only do farmers know that fertilizer is needed, they can 12. _______ calculate the exact amount. 13. ____________ (consequence), soil sampling makes 14. ______ possible for farmers to create the ideal conditions for their crops to grow and manage their resources effectively at the same time.While such applications are of enormous benefit, precision farming can reach a much higher level with the application of artificial intelligence. When 15. ______ (use) in farming machines, AI does contribute to increased crop yields as well as 16. ________ (simple) crop tracking, harvesting and processing. AI-controlled machines can now plant and harvest more crops at faster speeds 17. ________ humans ever could, while computer vision can distinguish weeds from crops. Moreover, algorithms based on data gathered by sensors, drones and satellites can work out site-specific management of the crops. With such efficiency and accuracy, this technology is ideal for farming crops that require delicate handling. For example, cotton farmers use drones with AI technology to carry out specialized tasks: they precisely remove the cotton plants' leaves by spraying chemicals only on the parts that need them. The drones autonomously navigate the fields, taking images of the crops, which are then analysed by software. Once the exact amount needed is determined, the drones spray the chemicals, while farmers can follow the whole process on a mobile device.Thanks to precision farming's close relationship with technology, the farming industry's capabilities can develop even further. Through the 18. _________ (integrate) of 5G technology and the Internet of Things(loT), as well as advances in deep-learning technologies, not only will larger amounts of data be available, but they will be processed more efficiently. Consequently, precision farming will become moreeffective and have an even greater impact on how we grow our food. Without doubt, the push for future developments in precision farming will benefit all of us-it will contribute to a greener, healthier and better-fed planet.Keys: 1. baking 2. to 3. reliable 4. highly 5. combination 6. massive 7. gathered 8. minimizes 9. capabilities 10. enabling 11. up 12. also 13. Consequently 14. It 15. used 16. simplified 17. than 18. integrationTea: China’s gift to the worldTea is currently the world's most popular drink, only after water. However, there was a time when tea was known only to the Chinese. So, how did tea 1. ________( origin) in China? And how did it get to conquer the world to the extent that people often describe something they really like as their "cup of tea"?2. _______ we know that tea drinking started in China, its true origin remains something of a mystery. Legend has it that about 5,000 years ago, Shennong came3. ______ tea when dried leaves blew into a pot of boiling water.4. _________ (follow) his discovery, tea was used as medicine,5. ________ (include) in meals and later offered as a refreshing drink to officials and noblemen.6. _________(event), it became a common drink enjoyed and embraced by all Chinese people.Over the years, as tea drinking became an important part of China's rich culture, the love of tea inspired many people to write about it. The great Tang poet Du Fu described his tea-drinking experience in poetic language, "On the high place the setting sun does shine. In the spring breeze, I sip my tea, sweet and fine." Lu Yu, a tea master, wrote The Classic of Tea, which remains the earliest and most famous7. ________ (detail) study on tea in the world, covering everything anyone could possibly want to know about Chinese tea.It is then not surprising that the beauty of tea was eventually revealed to a wider world.When the Tang and Song Dynasties needed strong Tibetan horses, the Tea Horse Road was born. Porters 8. ________ (carry) back-breaking loads of tea bricks made their way through dangerous snow-covered mountain passes in the most terrible weather conditions, to trade Sichuan and Yunnan tea for horses. Over time, the gift of tea was further delivered to Western Asia and Eastern Africa. Meanwhile, different sea routes also helped spread tea to other parts of the world. As early as the Tang Dynasty, Japanese monks came to study in China and took with them tea seeds and tea-making customs when 9. ________ (return) to Japan. Around the 1600s, tea 10.________(ship) to Europe from China by Portuguese and Dutch sea traders.The well-known writer Lin Yutang 11. _____(sum) up the power of tea when he said, "There is something in the nature of tea that leads us into a world of quiet 12. _________(contemplate) of life."Tea drinking is not just about refreshing the mind and body but also about appreciating the harmony between man and nature.From hillside to teacupGrowing teaTea plants grow best in warm, humid regions with well-drained soil. Consequently, they grow well on steep hillsides 13._______ heavy rain can easily drain away.China boasts many tea-growing areas, which can be divided into four distinct regions. Among them the south-west tea-growing region is the oldest while the region south of the Yangtze River produces the most tea in China.[ Subheading 1]_________Tea bushes are grown in rows and cut to a height of about one metre, 14. ______ (allow) tea pickers to easily harvest tea leaves. It takes up to five years for a tea bush to come to maturity, at 15._______ time the bud and top leaves are picked every few days. The tea-picking season may start as early as February and extend until late November.[ Subheading 2]________The process of turning tea leaves into the tea we love to drink is both complicated and highly technical. There are commonly between two and seven procedures 16. _______ （involve）in the processing of the fresh tea leaves. Any addition or 17. _______ (exclude) of these stages results in a different type of tea: green, yellow, white, black and oolong tea. Actually, all these different types of tea can be made from a single tea plant.[ Subheading 3]_________Tea can be enjoyed in many different ways. For example, the English drink their tea with milk, the Japanese enjoy powdered green tea, and in Morocco, mint tea 18. ________ (prefer). Tea drinking has also become part of many countries' culture. The English have their "afternoon tea", and in China, rightfully regarded 19. _____ the "birthplace" of tea, tea drinking can be both a common daily practice and a near 20._________(ceremony) experience.Keys: 1. originate 2. While 3. across 4. Following 5. included 6. Eventually 7. detailed 8. carrying 9. returning 10. was shipped 11. summed 12. contemplation 13. where 14. to allow 15. which 16. involved 17. exclusion 18. is preferred 19. as 20. ceremonial。

Chapter 1THERE was no possibility of taking a walk that day. We had been wandering, indeed, in the leafless shrubbery an hour in the morning; but since dinner (Mrs Reed, when there was no company, dined early) the cold winter wind had brought with it clouds so sombre, and a rain so penetrating, that further outdoor exercise was now out of the question.I was glad of it; I never liked long walks, especially on chilly afternoons: dreadful to me was the coming home in the raw twilight, with nipped fingers and toes, and a heart saddened by the chidings of Bessie, the nurse, and humbled by the consciousness of my physical inferiority to Eliza, John, and Georgiana Reed.The said Eliza, John, and Georgiana were now clustered round their mamma in the drawing-room: she lay reclined on a sofa by the fire side, and with her darlingsabout her (for the time neither quarrelling nor crying) looked perfectly happy. Me, she had dispensed from joining the group, saying, 'She regretted to be under the necessity of keeping me at a distance; but that until she heard from Bessie, and could discover by her own observation that I was endeavouring in good earnest to acquire a more sociable and childlike disposition, a more attractive and sprightly manner —something lighter, franker, more natural, as it were —she really must exclude me from privileges intended only for contented, happy little children.''What does Bessie say I have done?' I asked.'Jane, I don't like cavillers or questioners, besides, there is something truly forbidding in a child taking up her elders in that manner. Be seated somewhere; and until you can speak pleasantly, remainsilent.'A small breakfast-room adjoined the drawing-room, I slipped in there. It contained a bookcase; I soon possessed myself of a volume, taking care that it should be one stored with pictures. I mounted into the window- seat: gathering up my feet, I sat cross- legged, like a Turk; and, having drawn the red moreen curtain nearly close, I was shrined in double retirement.Folds of scarlet drapery shut in my view to the right hand; to the left were the clear panes of glass, protecting, but not separating me from the drear November day. At intervals, while turning over the leaves in my book, I studied the aspect of that winter afternoon. Afar, it offered a pale blank of mist and cloud; near, a scene of wet lawn and storm-beat shrub, with ceaseless rain sweeping away wildly before a long and lamentable blast.I returned to my book —Bewick's History of British Birds: the letter press thereof I cared little for, generally speaking; and yet there were certain introductory pages that, child as I was, I could not pass quite as a blank. They were those which treat of the haunts of sea-fowl; of 'the solitary rocks and promontories' by them only inhabited; of the coast of Norway, studded with isles from its southern extremity, the Lindeness, or Naze, to the North Cape —'Where the Northern Ocean, in vast whirls, Boils round the naked, melancholy isles Of farthest Thule; and the Atlantic surge Pours in among the stormy Hebrites. Nor could I pass unnoticed the suggestion of the bleak shores of Lapland, Siberia, Spitzbergen, Nova Zembla, Iceland, Greenland, with 'the vast sweep of the Arctic Zone, and those forlorn regionsof dreary space —that reservoir of frost and snow, where firm fields of ice, the accumulation of centuries of winters, glazed in Alpine heights above heights, surround the pole, and concentre the multiplied rigours of extreme cold '. Of these death-white realms I formed an idea of my own: shadowy, like all the half-comprehended notions that float dim through children's brains, but strangely impressive. The words in these introductory pages connected themselves with the succeeding vignettes, and gave significance to the rock standing up alone in a sea of billow and spray; to the broken boat stranded on a desolate coast; to the cold and ghastly moon glancing through bars of cloud at a wreck just sinking.I cannot tell what sentiment haunted the quite solitary churchyard, with its inscribed headstone; its gate, its two trees,its low horizon, girdled by a broken wall, and its newly risen crescent, attesting the hour of eventide.The two ships becalmed on a torpid sea, I believed to be marine phantoms.The fiend pinning down the thief's pack behind him, I passed over quickly: it was an object of terror.So was the black, horned thing seated aloof on a rock, surveying a distant crowd surrounding a gallows.Each picture told a story; mysterious often to my undeveloped understanding and imperfect feelings, yet ever profoundly interesting: as interesting as the tales Bessie sometimes narrated on winter evenings, when she chanced to be in good humour; and when, having brought her ironing-table to the nursery-hearth, she allowed us to sit about it, and while she got up Mrs Reed's lace frills, and crimped her nightcap borders, fed our eagerattention with passages of love and adventure taked from old fairy tales and older ballads; or (as at a later period I discovered) from the pages of Pamela, and Henry, Earl of Moreland.With Bewick on my knee, I was then happy: happy at least in my way. I feared nothing but interruption, and that came too soon. The breakfast- room door was opened.'Boh! Madam Mope!' cried the voice of John Reed; then he paused: he found the room apparently empty.'Where the dickens is she?' he continued. 'Lizzy! Gcorgy! (calling to his sisters) Jane is not here: tell mamma she is run out into the rain —bad animal!''It is well I drew the curtain, ' thought I, and I wished fervently he might not discover my hiding-place: nor would John Reed have found it out himself; he was notquick either of vision or conception; but Eliza just put her head in at the door, and said at once:'She is in the window-seat, to be sure, Jack.'And I came out immediately, for I trembled at the idea of being dragged forth by the said Jack.'What do you want?' I asked with awkward diffidence.'Say, "what do you want, Master Reed,"' was the answer. 'I want you to come here'; and seating himself in an arrn-chair, he intimated by a gesture that I was to approach and stand before him.John Reed was a schoolboy of fourteen years old; four years older than I, for I was but ten; large and stout for his age, with a dingy and unwholesome skin; thick lineaments in a spacious visage, heavy limbs and large extremities. He gorged himself habitually at table, which madehim bilious, and gave him a dim and bleared eye with flabby cheeks. He ought now to have been at school; but his mamma had taken him home for a month or two, ' on account of his dedicate health'. Mr. Mila, the master, affirmed that he would do very well if he had fewer cakes and sweetmeat sent him from home; but the mother's heart turned from an opinion so harsh, and inclined rather to the more refined idea that John's sallowness was owing to over-application, and, perhaps to pining after home.John had not much affection for his mother and sisters, and an antipathy to me. He bullied and punished me; not two or three times in the week, nor once or twice in a day, but continually: every nerve I had feared him, and every morsel of flesh on my bones shrank when he came near. There were moments when I was bewildered by the terror he inspired,because I had no appeal whatever against either his menaces or his inflictions; the servants did not like to offend their young master by taking my part against him, and Mrs Reed was blind and deaf on the subject: she never saw him strike or heard him abuse me, though he did both now and then in her very presence; more frequently, however, behind her back.Habitually obedient to John, I came up to his chair: he spent some three minutes in thrusting out his tongue at me as far as he could with out damaging the roots: I knew he would soon strike, and while dreading the blow, I mused on the disgusting and ugly appearance of him who would presently deal it. I wonder if he read that notion in my face; for, all at once, without speaking, he struck suddenly and strongly. I tottered, and on regaining my equilibrium retired back a step or two from his chair.'That is for your impudence in answering mamma a while since, ' said he, 'and for your sneaking way of getting behind curtains, and for the look you had in your eyes two minutes since, you rat!' Accustomed to John Recd's abuse, I never had an idea of replying to it: my care was how to endure the blow which would certainly follow the insult.'What were you doing behind the curtain?' he asked.'I was reading.''Show the book.'I returned to the window and fetched it thence.'You have no business to take our books; you are a dependant, mamma says; you have no money; your father left you none; you ought to beg, and not to live here with gentlemen's children like us, and eat the same meals we do, and wear clothes at our mamma's expense. Now, I'll teach you torummage my book-shelves: for they are mine; all the house belongs to me, or will do in a few years. Go and stand by the door, out of the way of the mirror and the windows.'I did so, not at first aware what was his intention; but when I saw him lift and poise the book and stand in act to hurl it I instinctively started aside with a cry of alarm: not soon enough however; the volume was flung, it hit me, and I fell, striking my head against the door and cutting it. The cut bled, the pain was sharp: my terror had passed its climax; other feelings succeeded.'Wicked and cruel boy!' I said. 'You are like a murderer —you are like a slave-driver —you are like the Roman emperors!'I had read Goldsmith's History of Rome, and had formed my opinion of Nero,Caligula, &c. Also I had drawn parallels in silence, which I never thought thus to have declared aloud.'What! what!' he cried. 'Did she say that to me? Did you hear her, Eliza and Georgiana? Won't I tell mamma? but first —'He ran headlong at me: I felt him grasp my hair and my shoulder: he had dosed with a desperate thing. I really saw in him tyrant: a murderer. I felt a drop or two of blood from my head trickle down my neck, and was sensible of somewhat pungent suffering: these sensations for the time predominated over fear, and I received him in frantic sort. I don't very well know what I did with my hands, but he called me 'Rat! rat!' and bellowed out aloud. Aid was near him: Eliza and Georgiana had run for Mrs Reed, who was gone upstairs; she now came upon the scene, followed by Bessieand her maid Abbot. We were parted: I heard the words: —'Dear! dear! What a fury to fly at Master John!''Did ever anybody see such a picture of passion!'Then Mrs Reed subjoined:'Take her away to the red-room, and lock her in there.' Four hands were immediately laid upon me, and I was borne upstairs.。

pets模拟试题及答案一、选择题（每题2分，共20分）1. Which of the following is NOT a common pet?A. DogB. CatC. FishD. Snake2. What is the best way to show affection to your pet?A. Yelling at itB. Petting it gentlyC. Ignoring itD. Hitting it3. How often should you feed a small dog?A. Once a dayB. Twice a dayC. Three times a dayD. As much as it wants4. What is the primary reason for taking your pet to the vet?A. GroomingB. VaccinationsC. PlaytimeD. Socialization5. What is the most important thing to consider when choosinga pet?A. PriceB. SpaceC. Time commitmentD. All of the above6. What should you do if your pet is lost?A. Give up looking for itB. Post flyers and notify local sheltersC. Wait for it to come homeD. Blame others7. Which of the following is NOT a sign of a healthy pet?A. Bright eyesB. Clean furC. LethargyD. Good appetite8. What is the best way to train a pet?A. Using harsh punishmentsB. Positive reinforcementC. Ignoring bad behaviorD. Only rewarding after perfect performance9. How can you prevent your pet from chewing furniture?A. Spraying furniture with bitter substancesB. Leaving it aloneC. Yelling at it after it chewsD. Providing it with no chew toys10. What is the first step in introducing a new pet to your home?A. Giving it a tour of the houseB. Letting it explore on its ownC. Keeping it in a confined spaceD. Introducing it to other pets immediately答案：1. D2. B3. B4. B5. D6. B7. C8. B9. A 10. C二、填空题（每题1分，共10分）11. A pet’s diet should be _______ and balanced.12. Regular exercise is important for a pet’s _______ and mental well-being.13. Vaccinations are a preventive measure against _______ diseases.14. A pet’s behavior can be influenced by its _______ environment.15. Spaying or neutering can help control the _______ of pets.16. Socialization is the process of getting a pet used to_______ and other animals.17. Pet insurance can cover _______ and emergency care.18. The life span of a pet can vary greatly depending on its_______.19. A pet’s health can be monitored through regular _______.20. Training a pet requires patience, consistency, and_______.答案：11. nutritious 12. physical 13. infectious 14. social 15. population 16. people 17. routine 18. species 19. check-ups 20. positive reinforcement三、简答题（每题5分，共30分）21. 为什么定期给宠物进行健康检查很重要？22. 描述一下宠物训练中正面强化法的工作原理。

高考英语双文阅读与学习：了不起的盖茨比-Chapter 1-02Chapter 1第五段：My family have been prominent, well-to-do people in this Middle Western city for three generations.笔记：this Middle Western city：美国中西部的一个城市。

美国中西部具体指的是美国纵贯南北的阿巴拉契亚山脉以西、密西西比河盆地以北的地区, 那里集聚着许多来自北欧的移民。

这个地区包括美国北达科他州（North Dakota）、明尼苏达州（Minnesota）、俄亥俄州（Ohio）、密苏里州（Missouri）、印第安纳州（Indiana）等。

prominent /ˈprɑmənənt /重要的; 著名的 well-to-do富裕的（be better off经济状况较以前（或较大多数人）好）翻译：在这座中西部城市，我家连续三代都算是有头有脸的上流人士。

The Carraways are something of a clan, and we have a tradition that we're descended from the Dukes of Buccleuch, but the actual founder of my line was my grandfather's brother, who came here in fifty-one, sent a substitute to the Civil War, and started the wholesale hardware business that my father carries on today.笔记：something of a(an)既可与表物的名词连用，亦可与表人的名词连用。

它表示不确定的程度(多少，有点，在某种程度上)： I'm something of a carpenter.我会点儿木工。

ABEmory Jensen是一名10岁的四年级学生，当穿梭在一场艺术展时，她用手指划过一面挂满艺术品的墙。

她难以置信地说道：“在其他地方这会让我陷入逆境，或者被赶出去。

”但是有视觉障碍的Emory没有被赶出去，因为她不是在一个典型的艺术馆里，而是置身于一次名为“dreamscapes”的完全身临其境的艺术体验中，作为学生实地考察旅行的一部分，旨在帮助向盲人学生阐述艺术。

“我们都可以感觉到，而不仅仅是我们只能看的东西。

”她接着说。

“这太棒了。

这种体验就像在《爱丽丝梦游仙境》中那样。

”这位学生还说她想和她的堂妹一起再来一次，她的堂妹患有同样的问题。

盲校项目的负责人Kate Borg说：“这些学生中的大多数可能从来没有去过艺术馆或真正去体验过艺术是什么。

”艺术通常专注于视觉效果，但“dreamscapes”旨在实现更多。

视觉，触觉和气味以及情感都是其中的重要部分。

它在所展示的艺术品中运用不同的声音，气味和物质，使人们穿越在具有不同主题的空间。

看着孩子们体验艺术给一些工作人员留下了深刻的印象。

“我抑制不住自己的眼泪，”“dreamscapes”经理Andrea Silva说。

“我从未见过游客对艺术如此感爱好和新奇。

我们希望全部人，特殊是孩子们能运用它。

”Borg说接触艺术至关重要。

“我们查阅了一项又一项谈论创建力和艺术对儿童的发展和成长至关重要的探讨。

”她说。

“而且仅仅因为一个孩子是盲人或视力障碍并不意味着他们不应当拥有相同的机会。

他们肯定须要接近艺术，我们必需更有创建力才能确保我们供应这样的机会。

”C开车上下班的人都知道交通堵塞是生活中不行避开的一部分。

但并非只有人类这样。

蚂蚁也来回于它们的巢穴和食物来源之间。

蚂蚁群体的生存依靠于有效地这样做。

对人类来说，汽车密度达到肯定程度时，车流变慢，从而造成交通堵塞。

亚利桑那州立高校的助理教授Motsch和他的同事们想知道蚂蚁是否也会遇到交通堵塞。

因此，他们通过在阿根廷蚁群和一个食物来源之间建立不同宽度的桥梁来限制交通密度。

pets3试题及答案一、单项选择题（每题1分，共10分）1. Which of the following is NOT a pet?A. DogB. CatC. BirdD. Snake2. What is the most common pet in the world?A. HamsterB. ParrotC. FishD. Dog3. What is the main reason for keeping pets?A. For foodB. For companionshipC. For huntingD. For fashion4. Which of the following animals is not suitable as a pet?A. RabbitB. TurtleC. MonkeyD. Goldfish5. What is the best way to care for a pet?A. Feeding it regularlyB. Giving it lots of toysC. Taking it for walksD. All of the above6. What is the most important thing to consider when choosinga pet?A. Its sizeB. Its temperamentC. Its dietD. Its lifespan7. Which of the following is NOT a benefit of having a pet?A. Stress reliefB. ExerciseC. EntertainmentD. Allergies8. What is the legal requirement for pet owners in some countries?A. VaccinationB. RegistrationC. InsuranceD. All of the above9. What is the main reason for pet abandonment?A. Lack of timeB. Lack of spaceC. Lack of moneyD. All of the above10. What is the best way to find a new home for a pet?A. OnlineB. Through a friendC. At a shelterD. All of the above二、填空题（每空1分，共10分）1. The most popular pet in the United States is the _______.2. A _______ is a small mammal that is often kept as a pet.3. The _______ is a common health problem for dogs.4. Pet _______ is a legal requirement in many places.5. A _______ is a place where unwanted pets can find a new home.6. The _______ is a common pet bird that can mimic human speech.7. The _______ is a small mammal that is often kept as a pet.8. A _______ is a type of pet insurance that covers medical expenses.9. The _______ is a common reason for pet allergies.10. The _______ is a type of pet that is often used for therapy.三、简答题（每题5分，共20分）1. Describe the process of adopting a pet from a shelter.2. Explain the importance of regular vet check-ups for pets.3. Discuss the benefits of walking a dog daily.4. What are some common mistakes pet owners make when it comes to feeding their pets?四、论述题（每题10分，共20分）1. Discuss the ethical considerations of keeping exotic animals as pets.2. Explain the role of pets in improving mental health.答案：一、单项选择题1. D2. D3. B4. C5. D6. B7. D8. D9. D10. D二、填空题1. dog2. hamster3. heartworm4. vaccination5. shelter6. parrot7. guinea pig8. pet insurance9. pet dander10. therapy animal三、简答题1. The process of adopting a pet from a shelter involves visiting the shelter, selecting a pet, completing an adoption application, meeting with an adoption counselor, and ifapproved, finalizing the adoption process.2. Regular vet check-ups for pets are important for early detection of health issues, ensuring vaccinations are up to date, and maintaining overall health and well-being.3. Walking a dog daily provides exercise, mental stimulation, and socialization opportunities, which are essential for the dog's physical and emotional health.4. Common mistakes pet owners make when feeding their pets include overfeeding, feeding inappropriate foods, and not providing a balanced diet.四、论述题1. Ethical considerations of keeping exotic animals as pets include the welfare of the animal, the legality of ownership, and the potential impact on native wildlife and ecosystems.2. Pets play a significant role in improving mental health by providing companionship, reducing stress, and offering a sense of purpose and responsibility.。

pet《新版1(标准版)》等级考试英语试卷test2全文共6篇示例，供读者参考篇1My Big English Test AdventureHi there! My name is Emma and I'm 10 years old. I just had the craziest day taking a really important English test called the PET 'New Version 1 (Standard)' Level Exam Test 2. It was super long and kind of hard, but I actually had a lot of fun with it! Let me tell you all about my big test adventure.It started bright and early this morning. My mom woke me up at 6am which is SO early for a Saturday! I was pretty grumpy at first, but then I remembered why I had to get up - for my huge English test! I got dressed super fast and ate a big breakfast of scrambled eggs, toast, and orange juice to fill up my brain.Then mom and I headed off to my school where the test was happening. There were kids from all over town there, looking just as nervous as me. We had to go to the gym and that's where all the desks were set up for the test. It felt just like taking one of my normal school tests, except there were a whole lot more kids there!The first part of the test was listening. The teachers played audio recordings and we had to answer multiple choice questions about what we heard. That wasn't too bad since I'm a pretty good listener. Although there was one weird story about a guy who lost his pet frog that completely stumped me!After listening, we moved right into the reading section. This is where things got really tough! The passages were all brand new topics I'd never read about before. There were texts about baking cupcakes, the history of skateboards, and even an article about ants. My brain was so fried trying to understand and answer the questions about all those new subjects.We did get a break for snacks and running around outside after the reading part, which was awesome. I desperately needed some fresh air and a snack to re-energize. I had a little bag of trail mix and an apple juice box. Yum!The next part was writing. We had to write a short story based on a picture they showed us. I actually thought this would be hard, but I ended up having a blast with it! The picture was of a kid and his dog, so I wrote all about the adventures they got into one summer day at the park. I used so many descriptive words to paint the picture in my mind. I was so proud of my little story!The very last section was speaking, which was probably the most nerve-wracking of all. They split us up into pairs and we had to take turns asking each other questions and responding. My partner asked me things like "What is your favorite subject in school?" and "What did you do last weekend?" I tried so hard to give detailed, grammatically correct responses. Phew!After what felt like an entire day (but was really only a few hours), the test was finally over. I've never been so relieved and exhausted at the same time! As I walked out with my mom, I just felt proud for giving that big challenge my all. Maybe I didn't ace every single part, but I know I tried my very best.A couple weeks later, I'll get my official results in the mail. I'm crossing my fingers that I did well enough to get that PET certificate! Even if I didn't though, the whole experience made me feel way more confident about my English skills. I'm just proud I could stick with it and work through all those different reading, writing, listening, and speaking sections.If you've got a big English test like that coming up, my advice is to get plenty of rest, fuel up with brain foods, and don't psych yourself out too much. You'll do great if you just stay focused and believe in yourself! Tests are hard but also kind of fun if you look at them like a challenge to rise to.Whew, I'm getting tired just thinking back on that crazy day again! I'm going to go take a nap before I have to start getting ready for my soccer game later. A kid's work is never done! Thanks for listening to my big English test adventure.篇2My Pet Level 1 English TestHi everyone! My name is Jenny and I'm going to tell you all about my recent experience taking the Pet Level 1 (Standard Version) English Test 2. I was a little nervous beforehand, but it ended up being really fun!The test had four sections - reading, writing, listening and speaking. We started with the reading section first thing in the morning. There were lots of different reading passages about all kinds of topics like animals, hobbies, school life and more. Some of the passages were conversations between people too.After each passage, there were multiple choice questions to test how well we understood what we had read. The questions asked things like who said what, what the main idea was, or asked us to fill in missing details. I tried my best to read everything really carefully so I could find the right answers.My favorite reading passage was the one about a girl and her pet hamster. It was so cute hearing about all the funny things her hamster would do, like stuffing its cheeks full of food! I have a hamster too, so I could really relate to that story.Once we finished the reading section, it was time for writing. We had to write a short story based on some pictures that were provided. The pictures showed a family going on a picnic in the park. In my story, I wrote about how they packed a yummy lunch, played fun games like frisbee, and had to run home when it started raining really hard! Writing stories is one of my favorite activities.After we turned in our writing samples, we took a break for snacks and recess before moving on to the listening part of the test. For this section, we listened to different recordings and had to answer comprehension questions just like we did for reading.One recording was about a boy giving instructions for taking care of a class pet over the weekend. Another one was a phone conversation between a mom and dad trying to figure out their family's schedule for the upcoming week. Listening carefully was so important to catch all the details!The final part of the test was the speaking section. We had to describe a series of pictures that told a story, like going on a tripor celebrating a birthday. The test administrators wanted to see how well we could put sentences together to explain what was happening in each picture.I love using my imagination, so this speaking part was really fun for me. For the pictures about a birthday party, I talked about how the family went to the mall to go shopping for presents, helped decorate with balloons and banners, and then sang "Happy Birthday" around a big cake. Speaking English clearly is something I'm working on, so tests like this help a lot.Even though there were a lot of different sections, I actually really enjoyed taking this Pet Level 1 English Test 2. It gave me a chance to practice all the reading, writing, listening and speaking skills I've been learning in my English classes at school. I'm already looking forward to taking the next level test!I'm sure I didn't get every single question right, but I tried my absolute best on each part of the test. No matter what my score ends up being, I'm proud of myself for giving it my all and not getting discouraged. Tests like this are great practice to keep improving my English abilities.Now I'm just counting down the days until I get my results back! I'll be sure to celebrate with my family if I pass on to the next Pet level. And if not, it's totally fine - I'll just study harderand try again next time. The most important thing is never giving up when learning a new language.Well, thanks for letting me tell you all about my Pet Level 1 test day! Being bilingual in English and my native language is so useful. I'm really glad my parents encouraged me to learn English from a young age. It opens up so many opportunities for the future.I hope this essay gave you a good idea of what to expect if you'll be taking the Pet English tests too. Study hard, don't stress too much, and most of all - have fun putting your English skills to the test! Learning a language should be an exciting adventure. OK, I'll sign off for now...bye!篇3Title: My Exciting Pet Exam Adventure!Hi there, friends! Today, I'm going to tell you all about my experience with the "Pet New Version 1 (Standard Edition)" level exam. It was a thrilling journey, and I can't wait to share it with you!First things first, what exactly is this "Pet" exam? Well, it's a test that measures your English language skills, and it's designedfor young learners like us. The "New Version 1 (Standard Edition)" level is the first step in this adventure, and it's all about showing how much we've learned so far.Now, let me tell you about my preparation for the exam. I studied really hard, practicing my reading, writing, listening, and speaking skills every day. My teacher gave me lots of practice tests, and my parents helped me with flashcards and fun games. It was a lot of work, but I knew it would all be worth it in the end.Finally, the big day arrived! I woke up early, had a healthy breakfast, and made sure I had all my supplies ready – pencils, erasers, and a big smile on my face! When I arrived at the exam center, I saw lots of other kids my age, and we were all feeling a little bit nervous but also excited.The exam itself was divided into different sections. First up was the reading part, where we had to read short passages and answer questions about them. I took my time, read carefully, and tried my best to understand every word. Next came the writing section, where we had to write a short story or essay. I let my imagination run wild and tried to use all the vocabulary and grammar I had learned.After a short break, it was time for the listening section. We had to listen to conversations or announcements and answerquestions based on what we heard. I focused all my attention and tried to catch every detail. Finally, the speaking part was my favorite! We had to have a short conversation with the examiner, introducing ourselves and answering some questions. I spoke clearly and confidently, remembering all the practice I had done.When the exam was over, I felt a huge sense of relief and accomplishment. I had given it my all, and no matter the result, I was proud of myself for trying my best.A few weeks later, the results arrived, and guess what? I passed the "Pet New Version 1 (Standard Edition)" level exam! I was over the moon with joy and couldn't wait to share the good news with my family and friends.Looking back, I realized that this exam was more than just a test – it was a learning experience that taught me the value of hard work, perseverance, and believing in myself. I'm already looking forward to the next level and can't wait to see what new adventures and challenges await me in the world of English language learning.So, if you ever have the chance to take the "Pet" exam, don't be afraid! Study hard, believe in yourself, and most importantly, have fun along the way. Who knows, you might just surprise yourself with how much you can achieve!篇4My Pet English Test AdventureHi friends! My name is Lily and I'm 10 years old. I just took the Pet English test level 1 and I want to tell you all about my exciting adventure with it!A few months ago, my English teacher Mrs. Roberts told our class that we would all be taking the Pet test. She said it's a really important English exam that shows how good our English skills are. I was a little nervous at first because tests can be scary. But Mrs. Roberts said not to worry and that if we studied hard, we'd do great.For weeks, we practiced all the things that would be on the test like reading, writing, speaking and listening. We did lots of practice tests too. My favorite part was the speaking practice because I love talking and telling stories! The reading was a bit harder for me though since some of the passages were pretty long with tricky vocabulary words.Finally, the big day came for the real Pet test! I had a good breakfast of eggs, fruit, and juice to keep my energy up. My mom wished me luck and dropped me off at school where the test washappening. There were kids from other schools there too, all taking the same Pet level 1 test.The test started with listening first. We had to listen to recordings and answer questions about what we heard. Like understanding directions or identifying the main idea. It was kind of fun picking out all the details I could understand.Next up was reading! We read different texts like stories, advertisements, and articles. Then we had to answer comprehension questions about them. Some passages were easier than others, but overall I tried my best. The key was going slowly and rereading parts I got stuck on.After a break for a snack, we did the writing section. We had to write a story based on some pictures, which was my favorite part! I loved using my imagination to make up a fun narrative. We also had to write emails, messages and other practical writing exercises.The last part was speaking, which made me a little nervous. I had to describe a scene, answer questions, and roleplay situations like ordering food or asking for directions. But I took a deep breath and reminded myself of all the practice I did. It ended up being not too bad!By the end, I was exhausted but so proud of myself for making it through such a big test. A few weeks later, I got my results in the mail and... I passed! I got a score that shows my English level is very good for my age. My parents were overjoyed and took me out for my favorite dinner of pizza to celebrate.Taking the Pet test level 1 was hard work but also really rewarding. It showed me how much English I've already learned and gave me confidence to keep studying hard. I'm so excited to continue improving my English skills and maybe take an even higher level Pet test in the future!If you're a kid learning English, I highly recommend trying out the Pet tests when you're ready. It's a great way to get experience with real English exams in a supportive setting. Just be sure to practice, stay calm on test day, and most importantly - believe in yourself! You've got this!篇5PET Exam Test 2Reading (25 points)Part 1 (5 points)Read the text and questions below. For each question, mark the correct letter A, B or C.My Favorite PetI have a pet dog called Buddy. He is a golden retriever and is three years old. Buddy has long golden fur and a friendly smile. He loves to play fetch and go for walks in the park. Every morning, I take Buddy out for a nice long walk before going to school. We stop at the playground and I throw his favorite tennis ball for him to catch.Buddy is a very good dog. He never makes a mess in the house and always comes when I call his name. At nighttime, Buddy sleeps in a cozy little bed next to my room. Sometimes I read him bedtime stories and he falls asleep listening to my voice. Buddy is my best friend and I love him very much!What kind of pet does the writer have?A. A dogB. A catC. A birdWhat color is Buddy's fur?A. BlackB. GoldenC. BrownWhat does Buddy like to play?A. FetchB. Hide and seekC. Tug of warWhere does Buddy sleep at night?A. On the couchB. In the writer's bedC. In his own little bedHow does the writer feel about Buddy?A. She loves him a littleB. She doesn't like himC. She loves him very muchPart 2 (10 points)Read the text and answer the questions below in full sentences.My Summer VacationLast summer, my family went on an amazing vacation. We drove five hundred miles to a beautiful beach town called Seashore City. When we arrived, I was so excited to see the bright blue ocean and the soft sandy beaches. Our hotel room had a balcony with an incredible view of the water.We spent our days swimming, building sandcastles, and collecting pretty seashells. In the evenings, we would walk along the beach boardwalk and get ice cream cones. My favorite flavor was chocolate chip! One night, we even saw a outdoor movie playing on a huge screen right on the beach. It was so much fun sitting under the stars watching a film.On the last day, we went on a boat tour to look for dolphins. The tour guide told us lots of interesting facts about the ocean and marine life. We were lucky enough to spot three gray dolphins swimming and jumping right next to our boat! I will never forget that amazing sight.Our vacation ended too soon and before I knew it, we had to pack our bags and make the long drive back home. I had such an incredible time at Seashore City and made so many wonderful memories. I can't wait to go back again next summer!Where did the writer go on vacation?How did the family travel to get there?What did the writer enjoy doing at the beach?What special event did the family attend one night?What animal did the writer get to see up close on the boat tour?Part 3 (10 points)Read the definitions and write the correct word from the word bank.Word Bank: afford, recycle, community, volunteer, donate, environment, pollution, endangeredTo give money, goods or time freely to help a person or cause. ________Animals or plants that may soon disappear forever. ________A group of people living together in one place or area.________Damage caused to air, water or land by harmful substances. ________To change waste into reusable materials. ________The natural world of land, air, water, plants and animals.________To give some of your time to help others for free. ________To be able to pay for something using your money. ________Writing (25 points)You have read a book about a young wizard who goes on an exciting magical adventure. Write a book review sharing your opinion of the story. Include details about the main character, the plot, and whether you would recommend the book to other students your age. Your review should be 200-250 words.Speaking (25 points)Part 1: Answer questions about yourself.Examples:• What is your favorite subject in school?• What games or sports do you like to play?• What do you like to do after school?Part 2: Describe the picture.• What do you see in the picture?• What is happening?• How do you think the people/animals feel?Part 3: Role-play situation.• A new student is joining your class. Introduce yourself and show the new student around the school. Explain where things are located like the library, playground, cafeteria etc.Part 4: Make a case persuading your parents to get you a pet.• Explain what kind of pet you want.• Give reasons why you want this pet and why pets are good for kids.• Promise how you will take care of it and be responsible.篇6My Pet Level 1 English Test ExperienceHi everyone! My name is Emma and I'm 10 years old. I just took the pet《新版1(标准版)》等级考试英语试卷test2 and I wanted to tell you all about it. It was a really big test for me because English is still pretty hard. But I studied a lot and gave it my best shot!The first part of the test was the listening section. I had to listen to some conversations and answer questions about what I heard. There were people talking about things like their favorite foods, weekend plans, after school activities and more. Listening is one of the hardest parts for me because the people talk so fast! But I tried my best to listen carefully to every word.After the listening section, we moved on to the reading part. We had to read a few different stories and passages then answer comprehension questions about them. One story was about a girl and her pet hamster which was really cute. Another one was about two friends going on a camping trip with their families. The passages weren't too too long which was good because my eyes start to get tired if I have to read a lot without taking breaks.The writing section came next. We had to write a short story based on some picture prompts. The pictures showed a boy and his dog playing outside. So I wrote a story about a kid who loved spending time with his puppy and all the fun adventures they would go on together. I tried to use a lot of descriptive words to make my story interesting and detailed.Then it was time for the speaking section which made me pretty nervous! We had to answer some questions and also describe a series of pictures to demonstrate our English speakingabilities. The pictures were about a family going on vacation which was a fun topic. I just tried to slow down, pronounce each word clearly, and not be afraid to take pauses if I needed to think for a second.Finally, the last part was the integrated skills section where we had to demonstrate reading, writing, listening and speaking all combined. We read a short passage about after school clubs, listened to a conversation about the same topic, then had to give a spoken summary of the key points. It was pretty challenging to put all those skills together at once!Overall, I worked really hard to prepare for this test over the past few months. My teachers gave me lots of practice materials and my parents helped me study at home too. There were some parts that were pretty difficult for me, but I felt good about the effort I put in. No matter how I scored, I'm proud of myself for giving it my best. Tests can be stressful but it's important to stay positive and have fun while learning English.Now I get to take a break and enjoy my summer vacation! Over the next few months I'll keep practicing my English skills through reading, watching shows, and playing language games. I love learning new words and phrases to better communicate with people from all around the world. English opens up so manydoors and opportunities. I'm already looking forward to taking the next level of the test when I'm older!Well, that's my experience with the pet《新版1(标准版)》等级考试英语试卷test2. It challenged me for sure, but I had fun along the way. Thanks for reading my story! Let me know if you have any other questions.。

POCKET GUIDE TO T IGHTENING TECHNIQUEChapter 1-62P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U EEPOCKETChapter .1. Why threaded fasteners? .2. The screw joint .3.4. Effect of lubrication .5.6.3P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q UPOCKET GUIDE TO TIGHTENINGT ECHNIQUEThis booklet provides an introduction to the technique of us-ing threaded fasteners for assembling components, the ap-plication of power tools for the assembly and the influence oftool selection on the quality of the joint.1. WHY THREADED FAS TENERS?There are several ways of securing parts and components toeach other, e.g. gluing, riveting, welding and soldering.However, by far the most common method of joining compo-nents is to use a screw to clamp the joint members with anut or directly to a threaded hole in one of the components.The advantages of this method are the simplicity of designand assembly, easy disassembly, productivity and in the end– cost.2. THE SCREW JOINTA screw is exposed to tensile load, to torsion and sometimesalso to a shear load.The stress in the screw when the screw has been tightened tothe design extent is known as the pre-stress.The tensile load corresponds to the force that clamps the jointmembers together. External loads which are less than theclamping force will not change the tensile load in the screw.On the other hand, if the joint is exposed to higher externalloads than the pre-stress in the bolt the joint will come apartand the tensile load in the screw will naturally increase untilthe screw breaks.4P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U EP O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U ET orsion in the screw results from friction between the threads in the screw and the nut.Some screws are also exposed to shear loads which occur when the external force slides the members of the joint in relation to each other perpendicular to the clamping force. In a properly designed joint the external shear force should be resisted by the friction between the components. A joint of this kind is called a friction joint. If the clamping force is not sufficient to create the friction needed, the screw will also be exposed to the shear load. Joints are frequently designed for a combination of tensile and shear loads.The screw is made up of the shank and the head. T he shank is threaded, either for part of its length or for the full length from the end to the head. Longer screws are usually only partly threaded. T here is no need to make a thread longer than is necessary to tighten the joint as this will only make the screw more expensive and reduce the tensile strength.The dimensions of threads, the shape of the thread and the pitch, i.e. the distance between successive threads, have been standardized. In practice there are only two different stand-ards used today in industry; the Unified standard UN, origi-nally used in the Anglo-Saxon countries, and the European Metric standard M.Shear load and tensile load.Shear load3. CLAMPING FORCEIn general it is desirable that the screw is the weakest memberof the joint. An over-dimensioned screw makes the productboth heavier and unnecessarily expensive. As a standard screwis usually comparatively inexpensive it is preferable that thescrew should be the first part to break.Furthermore, in most cases the dimensions of the screw arenot critical for the quality of the joint. What is decisive is theclamping force, i.e. whether it is sufficient to carry all the loadfor which the joint is designed, and whether the joint will re-main tight enough to prevent loosening if exposed to pulseloads.The problem is that there is no practical way to measure theclamping force in normal production situations. Consequentlythe value of the clamping force is usually referred to as thetightening torque.As the clamping force is a linear function of both the turningangle of the screw and the pitch of the thread, there is a directrelation between the clamping force and the tightening torquewithin the elastic range of the screw elongation. However, onlyabout 10% of the torque applied is transferred into clampingforce. T he remaining tightening force is consumed in friction inthe screw joint – 40% of the torque to overcome the friction inthe thread and 50% in friction under the screw head.6P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U E4. EFFECT OF LUBRICATIONIf a screw is lubricated, the friction in the threads and underthe head is decreased and the relation between tighteningtorque and clamping force is changed. If the same torque isapplied as before lubrication, a lot more torque will be trans-formed into clamping force. At worst this might lead to thetension in the screw exceeding the tensile strength and break-ing of the screw.On the other hand, if the screw is completely dry of lubricantthe clamping force might be too small to withstand the forcesfor which the joint is designed, with the risk that the screwbecomes loose.Table 1. Friction in threads ofdifferent material.P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U E75. SCREW QUALITY CLASSIFICATIONWhen a screw is tightened and the clamping force starts tobuild up, the material of the screw is stressed. After a shorttime when the thread settles the material will stretch in pro-portion to the force. In principle, this elongation will continueuntil the stress in the screw is equal to the tensile strengthat which the screw will break. However, as long as the elon-gation is proportional to the stress the screw will regain itsoriginal length when the load is removed. T his is known asthe elastic area.StressAt a certain stress, known as the yield point, plastic defor-mation of the material in the screw will occur. However, thescrew will not break immediately. T orque will continue toincrease but at a lower torque rate during the deformationabove the yield point. T he plastic deformation will result in apermanent elongation of the screw if the joint is loosened.For very accurate clamping force requirements this area issometimes deliberately specified for the tightening process.Beyond the plastic area breakage occurs.8P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U E9P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U EM-Threaded screwboltsTightening torque Nm, according to ISO 898/1The material qualities of screws are standardized, i.e. the amount of tensile stress they can be exposed to before the yield point is reached and before breakage occurs. All screws should be marked according to their Bolt Grade – a classifica-tion standard in a two-digit system where the first digit refers to the minimum tensile strength in 100 N/mm 2 and the second digit indicates the relation between the yield point and the minimum tensile strength. For example: Bolt Grade 8.8 desig-nates a screw with 800 N/mm 2 minimum tensile strength and a yield point of 0.8 x 800 = 640 N/mm 2.Table 2. T able for differentc lasses of screws.Example of screw d esignation.6. JOINT TYPESScrew joints vary not only in size but also in type, whichchanges the characteristics of the joints. From a tighten-ing point of view the most important quality of a joint is the“hardness”. In figures this can be defined as the “torque rate”,which is the tightening angle necessary to achieve the recom-mended torque of the screw dimension and quality in ques-tion measured from the snug level – the point at which thecomponents and the screw head become tight.The torque rate can vary considerably for the same diameterof screw. A short screw clamping plain metal componentsreaches the rated torque in only a fraction of a turn of thescrew. T his type of joint is defined as a “hard joint”. A jointwith a long screw that has to compress soft components suchas gaskets or spring washers requires a much wider angle,possibly even several turns of the screw or nut to reach therated torque. T his type of joint is described as a soft joint.Obviously the two different types of joints behave differentlywhen it comes to the tightening process.10P O C K E T G U I D E T O T I G H T E N I N G T E C H N I Q U E7.T orque and angle8.Measurement methods9.The tightening process10.Mean shift11.Standards for measurement。

Suggested answers to Practical Workbook for SBACh 1 Introducing biologyPractical 1.1 Design an investigation of the effect of freshpineapple on the setting of jellyPropose a hypothesis (p. 1-2)It is the fresh pineapple that causes the jelly to remain in liquid form.Design and perform an experiment (p. 1-2)1(Answer varies with Ss. The recommended quantity of jelly powder and water is stated on the packet of the jelly powder. Jelly will not set if it is too dilute.)2Method II. This makes sure the concentrations of the jelly solutions in different containers are the same.A Identifying variablesBDesigning the set-upC Collecting data1 (Answer varies with Ss.)2 Repeat the experiment a few more times.D Risk assessment and safety precautions1 During the preparation of jelly solution, the hot water may burn our body.The knife used to cut the pineapple is very sharp and may cut our fingers.2 Wear a pair of thick gloves when handling hot water.Handle the knife with care.Write an experimental report (p. 1-4)ObjectiveTo investigate the effect of fresh pineapple on the setting of jelly.HypothesisIt is the fresh pineapple that causes the jelly to remain in liquid form. Apparatus and materials1 electronic balance1 refrigerator2 beakers (500 cm3)1 measuring cylinder (100 cm3)2 plastic containers 2 glass rods1 knifefresh pineapple hot waterjelly powderProcedure1Cut a fresh pineapple into small pieces.2Add 50 g of jelly powder and 200 cm3 of hot water to a beaker. Stir the mixture with a glass rod until all the jelly powders dissolve.3Pour 100 cm3 of jelly solution into two containers respectively. Leave the jelly solutions at room temperature for one hour.4Put the small pieces of fresh pineapple into one of the containers. Then, refrigerate two containers overnight.5Observe any changes of jelly solutions in the two containers on the next day.ResultsThe jelly without fresh pineapple set.The jelly with fresh pineapple does not set.Analysis and discussion1It is used to confirm that the presence of fresh pineapple is the only factor that prevents the jelly from setting.2(Answer varies with the design.)ConclusionThe presence of fresh pineapple prevents the jelly from setting.Ch 2 The cell as the basic unit of lifePractical 2.1 Observation with a light microscopeResults (p. 2-4)(Drawings vary with the cells observed. Drawings of human cheek cells and onion epidermal cells are given as examples.)Questions (p. 2-4)1To allow entry of a suitable amount of light. A dim image may result if there is insufficient light while a faint image may result if the light is too bright.2The coarse adjustment knob leads to a larger degree of movement of the body tube.Any downward movement of the body tube controlled by the coarse adjustment knob may damage the objective or the slide because the distance between the objective and the slide is very small.4Towards the left. An inverted image is formed in the microscope. It moves in a direction opposite to the actual movement of the flatworm.Practical 2.2 Preparation of temporary mounts of animal cellsand tissuesResults (p. 2-7)Questions (p. 2-8)1To flatten the specimen so that they can be seen easily in one plane of focus for the objective lens. To prevent the objective lens from getting dirty by touching the specimen or the mounting medium. To prevent the specimen from drying out because ofevaporation. To protect the specimen from being damaged.2 Cell membrane, nucleus and cytoplasm.3 Anywhere inside the cell.4 No. / Yes, they have small vacuoles.Practical 2.3 Preparation of temporary mounts of plant cellsand tissuesResults (p. 2-12)Questions (p. 2-13)1 Cell wall, cell membrane, nucleus, cytoplasm, chloroplast and granule.2 Near the side of the cell.3 No. Not all of them contain chloroplasts or chlorophyll. Only those with chloroplasts aregreen.4 Similarities: Both of them have a nucleus, a cell membrane and cytoplasm.Differences:1Plant cells are often larger than animal cells.2Plant cells have a definite shape while the animal cells do not.3 Plant cells have a thick cell wall and some have chloroplasts. Animal cells do nothave cell walls or chloroplasts.4Plant cells usually have a large vacuole while animal cells do not.Practical 2.4Examination of prokaryotic and eukaryotic cells2Questions (p. 2-16)1 Actual size of E. coli =00060cm14 = 0.00023 cm = 2.3 μm Actual size of Guinea pig bone marrow cell = 50012cm13 = 0.00104 cm = 10.4 μmGuinea pig bone marrow cell is larger than E. coli.2 Cell X is a eukaryotic cell because it has a true nucleus.Ch 3 Movement of substances across cell membrane Practical 3.1 Demonstration of osmosis using dialysis tubing (p. 3-2)Questions (p. 3-3)1 Its small bore gives a more obvious change in liquid level.2 Sucrose solution on the outside of the tubing will affect the result. Rinsing the tubingensures no such sucrose solution is present.3a There is a net water movement from distilled water to sucrose solution.b Osmosis.c Differential permeability.4 After a certain period of time, the force produced by the weight of the liquid columnbalances the force developed by the water potential gradient.5 a The liquid level will rise faster and higher.b The liquid level will drop and the tubing will eventually shrink.Conclusion (p. 3-3)When sucrose solution is separated from distilled water by a dialysis tubing, osmosis takes place and there is a net movement of water molecules from distilled water to sucrose solution.Practical 3.2 Demonstration of osmosis using living animaltissue3Questions (p. 3-6)1 Set-up B is a control. It shows that any change in liquid level in set-up A is due to theconcentrated sucrose solution.2 Distilled water has a higher water potential than concentrated sucrose solution, so there isa net movement of water from the distilled water to concentrated sucrose solution throughthe differentially permeable animal tissues by osmosis. The volume of liquid inside the thistle funnel increases and the liquid level rises.Conclusion (p. 3-7)Living animal tissues are differentially permeable. When solutions with different water potential are separated by living animal tissues, osmosis takes place.Practical 3.3 Study of osmosis in red blood cells(p. 3-9)Questions (p. 3-9)1 0.9% sodium chloride solution is isotonic to the red blood cells. At this concentration, thered blood cells appear normal. It shows that there is no net movement of water into or out of the cells because there is no difference in water potential between the cells and itssurrounding.2 0% and 0.45% sodium chloride solutions are hypotonic to the red blood cells. At theseconcentrations, the red blood cells swell and burst. It shows that the water potential of the red blood cells is lower than that of the sodium chloride solution. Water enters the red blood cells by osmosis.3 1.35% and 1.8% sodium chloride solutions are hypertonic to the red blood cells. At theseconcentrations, the red blood cells shrink and become wrinkled. It shows that the water potential of the red blood cells is higher than that of the sodium chloride solution. Water leaves the red blood cells by osmosis.Conclusion (p. 3-10)When red blood cells are put in a hypotonic solution, water enters the cells by osmosis.The red blood cells swell and finally burst.When red blood cells are put in a hypertonic solution, water leaves the cells by osmosis.The red blood cells shrink.Practical 3.4 Study of osmosis in living plant cells3Questions (p. 3-13)1 To prevent the evaporation of sucrose solution, which may change its water potential andaffect the results. This also provides a flat surface for observation and keeps the objective lens of the microscope clean.2 The cytoplasm swells up gradually until the cell membrane presses tightly against the cellwall.3 No. This is because the concentration of the content / water potential of each cell varies.Conclusion (p. 3-13)When the surrounding fluid has a lower water potential than the plant cells, water leaves the cells by osmosis. The cells finally become plasmolyzed and flaccid. When the water potential of the surrounding fluid increases, water will enter the cells by osmosis. The cytoplasm expands and the cells become turgid.Practical 3.5 Study of osmosis in living plant tissue(p. 3-15)Questions (p. 3-16)1 Osmosis cannot takes place across the potato peel because the peel is impermeable towater. Any peel left on the potato strips will affect the result.2 To prevent the evaporation of water which may change the concentration of the liquids inthe set-ups and affect the results.3 To absorb the surplus water on the surface of the potato strips which may increase theweight of the potato strips and affect the results.4 To minimize the water loss from the potato strips by evaporation. Any water loss willdecrease the weight of the potato strips and affect the results.5 The potato strips in distilled water become heavier. This is because the water potential ofdistilled water is higher than that of the potato cells. Water enters the potato strips byosmosis.6 The weight of the potato strips in 10% sucrose solution changes very slightly. This isbecause the water potential of 10% sucrose solution is nearly the same as that of the potato cells. There is almost no net movement of water into or out of the potato strips.7 The potato strips in 20% sucrose solution become lighter. This is because the waterpotential of 20% sucrose solution is lower than that of the potato cells. Water leaves the potato strips by osmosis.Conclusion (p. 3-17)Living plant tissues are differentially permeable. When living plant tissues are placed in solutions with different water potential, osmosis takes place.Practical 3.6 Examination of phagocytosis in AmoebaResults (p. 3-19)Questions (p. 3-19)1 Amoeba takes in food particles by phagocytosis: when Amoeba gets close to the foodparticles, pseudopodium starts to form to surround the food particles. The whole food particles are finally engulfed by the Amoeba.2 Phagocytosis is important for:1 the nutrition of some single-celled organisms, e.g. Amoeba engulfs food particles byphagocytosis;2 body defence against diseases, e.g. in humans and other mammals, certain whiteblood cells engulf harmful microorganisms by phagocytosis.Ch 4 Enzymes and metabolismPractical 4.1 Demonstration of the breaking-down action ofenzymes(p. 4-3)Questions (p. 4-3)1 This increases the surface area for reactions.2 Grinding action produces heat. The high temperature resulted may denature any enzymepresent in the tissues.3 The gas given off is oxygen.4 a It is a control to show that no oxygen is given off from the liver extract.b It is a control to show that no oxygen is given off from the hydrogen peroxide.5 Liver extract reacts with hydrogen peroxide to produce oxygen.6 No. This experiment only shows that the breakdown of hydrogen peroxide is speeded upby the liver extract. Boiled liver extract, instead of fresh liver extract, can be used in a further experiment. If boiled liver extract has no catalytic action, it is more likely that the reaction is catalysed by an enzyme.7 Yes. For the three test tubes, only one variable (the sample) is changed at a time, othervariables (e.g. the volume and temperature of hydrogen peroxide, liver extract anddistilled water) are kept constant.Conclusion (p. 4-4)The breakdown of hydrogen peroxide is catalysed by the liver extract, probably by an enzyme in the liver tissues. Nevertheless, further experiments should be done to confirm this.Practical 4.2 Investigation of the effect of temperature onenzyme activity4Questions (p. 4-7)1 To ensure that the amylase and starch solutions inside the tubes reach the respectivetemperatures before the reaction starts.2 To prevent the changing of the condition of a mixture by any residue in the dropper.3 Amylase is inactive at low temperatures. Its activity increases with temperature and is thehighest at 60°C. Afterwards the activity decreases and stops at 100°C. With a rise intemperature, the kinetic energy of amylase and starch molecules increases. They collide and react more frequently. As the temperature increases further, the active sites of amylase become distorted (i.e. the enzyme is denatured) and the reaction rate decreases. At 100°C, all amylase is denatured and no reaction takes place.4 a Starch will be digested and blue-black colour will disappear. This is because theinactive amylase will resume its activity with an increase in temperature.b Starch will not be digested and blue-black colour will remain. This is because theactivity of the denatured amylase will not restore even when it is cooled.5 Measuring the rate of appearance of maltose molecules.Conclusion (p. 4-8)Amylase is inactive at low temperatures. Its activity increases with temperature until it reaches a maximum. Afterwards the activity decreases and stops.Results(p. 4-10)Questions(p. 4-11)1 To ensure the invertase has sufficient time to catalyse the breakdown of sucrose intoglucose and fructose.2 (Answer depends on results.)3 a No or less brick-red precipitate will be formed. This is because extremely low pH willdenature the invertase and reduce the enzyme activity.b No or less brick-red precipitate will be formed. This is because extremely high pHwill denature the invertase and reduce the enzyme activity.4 Weighing the precipitate formed. / Using an arbitrary system of ‘+’ to denote the relativeamount of precipitate.Conclusion(p. 4-11)Invertase is most active in the acidic medium (pH 5.2) and less active in the neutral and alkaline medium.activityResults (p. 4-13)Questions (p. 4-14)1 It is a control to show that the activity of invertase is slowed down or stopped by theinhibitor.2 No or less brick-red precipitate is formed in tubes A and B because copper(II) ions andsilver ions are inhibitors of invertase. They slow down or stop the activity of invertase.Brick-red precipitate is formed in tube C because the activity of invertase is not affected by any inhibitor.3 Whether an inhibitor is competitive or non-competitive can be found out by increasing thesubstrate concentration of the reaction medium. The reaction rate will be increased in case of competitive inhibition, but not in case of non-competitive inhibition.Conclusion (p. 4-14)Copper(II) ions and silver ions are inhibitors of invertase. They slow down or stop the activity of invertase.Practical 4.5 Investigation of protease activities in different fruit juicesResults (p. 4-17)Questions (p. 4-17)1 It is a control to show that the formation of the clear zones is due to the fruit juices.2 Proteases in the fruit juices break down the white milk protein nearby. Therefore, thewhite colour of the milk disappears and the clear colour of the agar is shown around the wells containing fruit juices.3 (Answer depends on results.)4 It is because the proteases in pineapple are denatured by the high temperature during thecanning process.5 The proteases in fresh pineapple can break down the proteins in beef steak. Leaving beefsteak in contact with slices of pineapple for half an hour allows enough time for theenzymes to work.Conclusion (p. 4-18)Pineapple, kiwi fruit, papaya and guava contain proteases that can break down proteins, but their activities differ from one another.Practical 4.6 Design an investigation of the effectiveness ofdifferent biological washing powdersDesign and perform a fair test (p. 4-20)1 Protease. / Lipase.2 By mixing the washing powder with distilled water well.3 (Answer varies with Ss. The recommended quantity of washing powder and water is statedon the packet of the washing powder. This ensures the washing powder works in the best conditions.)A Identifying variablesB Designing the set-up(Answer varies with Ss.)C Collecting data1 (Answer varies with Ss.)2 Provide the optimum temperature and pH for the enzyme to work.3 Repeat the experiment a few more times.D Risk assessment and safety precautions1 (Answer varies with the design.)2 (Answer varies with the design.)Write an experimental report (p. 4-22)Objective(Answer varies with Ss.)Apparatus and materials(Answer varies with Ss.)ProcedureSs can carry out the experiment in a number of ways.Ss may conduct the experiment by using a milk-agar plate (see Practical 4.5).Another method is using two test tubes containing equal volumes of boiled egg white cubes. Add the two washing powder solutions into the test tubes and compare the rate of dissolving of the egg white cubes.Results(Answer varies with Ss.)Analysis and discussion1 (Answer depends on results.)2 No. We should consider the price of each brand.3 It is because enzyme activity increases at a higher temperature.4 It is because proteins in silk and wool will be broken down by the proteases.5 (Answer varies with the design.)Conclusion(Answer varies with Ss.)Ch 5 Food and humansPractical 5.1 Detection of food substances by food tests Results (p. 5-5)A Test for glucose using Clinistix paperB Test for reducing sugars using Benedict’s testC Test for starch using iodine testD Test for lipids using grease spot testE Test for proteins using Albustix paperF Test for vitamin C using DCPIP solutionQuestions (p. 5-6)1 No. This is because these food tests are qualitative tests for showing the presence ofcertain food substances. They are not quantitative tests.2 The water bath has a better control over the temperature and can prevent bumping of themixture.3 As the red colour of the blood will mask the results of the Benedict’s test, the blood sampleshould be diluted with distilled water first. Alternatively, the blood sample should becentrifuged and the plasma collected is used for the Benedict’s test.4 The translucent spot caused by lipids is permanent. On the contrary, the translucent spotcaused by water disappears as water evaporates.5 Lipids but not proteins dissolve in organic solvent. Thus, the translucent spot caused bylipids disappear whereas the one caused by proteins remains on the filter paper.6 a Boiling destroys the reducing property of vitamin C. Thus, only the vitamin Csolution that has not been boiled can reduce the blue DCPIP solution and decolourizeit.b Do not boil or overheat fruits and vegetables.7 No. Glucose, like vitamin C, is reducing and will decolourize DCPIP solution no mattervitamin C is present in the sample or not.Practical 5.2 Investigation of the food substances in commonfoodstuffsResults (p. 5-12)Question (p. 5-12)(Answer depends on the types of foods tested.)Practical 5.3 Design an investigation to compare the amount ofvitamin C in different fruits and vegetables Design and perform a fair test (p. 5-14)1 Yes. Accurate measurement is necessary because a comparison of vitamin C content indifferent fruits and vegetables is needed.2 Fruits or vegetables that have juices very pale in colour. The pale colour of the juices willnot mask the decolourization of DCPIP solution.A Identifying variablesB Designing the set-up(Answer varies with Ss.)C Collecting data1 (Answer varies with Ss.)2 Use less DCPIP solution or a more dilute DCPIP solution.3 Take any dilution factor of the juices into consideration in the comparison of vitamin Ccontent.Repeat the experiment with more samples from the same types of fruits and vegetables.D Risk assessment and safety precautions1 The knife used to cut fruits and vegetables is very sharp and may cut our fingers.2 Handle the knife with care.Write an experimental report (p. 5-16)ObjectiveTo compare the vitamin C content in different fruits and vegetables.Apparatus and materials10 test tubes1 test tube rack10 droppers1 measuring cylinder (10 cm3) 1 mortar and pestle1 knife 1 filter funnelfilter paper or fine muslin0.02% DCPIP solutiondistilled waterfruits and vegetables (e.g. orange, lemon, cabbage)Procedure1 Cut the fruit or vegetable into small pieces.2 Put the small pieces into a mortar and grind with a small known quantity of cool distilledwater (if necessary) using the pestle.3 Squeeze the ground materials through several layers of pre-moistened fine muslin or filterthem through a filter paper to remove the debris. Collect the juice extracted.Skip this step if a fine and fairly colourless suspension is obtained.4 Put 1 cm3 of DCPIP solution in a test tube.5 Use a dropper to add the juice, drop by drop, to theDCPIP solution until the solution is decolourized. Recordthe number of drops of juice added.6 Repeat steps 4 and 5 with the juices extracted from different fruits and vegetables. If thedecolourization is too quick (i.e. the juice is too concentrated), dilute the juice by a known volume of distilled water and repeat steps 4 and 5 again. Take this dilution factor into consideration in the comparison of vitamin C content.7 Repeat steps 4 and 5 with distilled water. It is a control.ResultsAnalysis and discussion1 (Answer depends on the results.)2 (Answer depends on the results.)3 Reducing property.4 a The vitamin C content will decrease as vitamin C will be oxidized by the air.b The vitamin C content will decrease as vitamin C will be destroyed by hightemperatures.5 The vitamin C in the juices will be oxidized by the air.The observation of complete decolourization of DCPIP solution is subjective, especially when the juices are coloured.There are other reducing substances, e.g. glucose and fructose, in the juices.6 Fruits or vegetables that have juices very dark in colour cannot be used. The dark colour ofthe juices masks the decolourization of DCPIP solution.Conclusion(Answer depends on the results.)6 Nutrition in humansPractical 6.1 Examination of the mammalian alimentary canal and its associated glandsQuestions (p. 6-2)1A MouthB OesophagusC StomachD DuodenumE PancreasF AppendixG Ileum H CaecumI Liver J ColonK Rectum L Anus2 A→B→C→D→G→J→K→L4 The salivary glands, the pancreas and the liver.Practical 6.2 Design an investigation of the action of digestiveenzymesDesign and perform an experiment (p. 6-4)1 Proteins.2 37°C. To simulate the body temperature at which pepsin works well.A Identifying variablesB Designing the set-up(Answer varies with Ss.)C Collecting data1 (Answer varies with Ss.)2 Provide a higher temperature, use smaller egg white cubes instead of a large one, raise theegg white cube from the bottom of the test tube by using a toothpick, etc.3 Repeat the experiment a few more times.D Risk assessment and safety precautions1 The knife used to cut the hard-boiled egg is very sharp and may cut our fingers.Dilute hydrochloric acid is corrosive and dilute sodium carbonate solution is irritant.2 Handle the knife with care. Wear disposable gloves. Wash hands thoroughly with liquidsoap and water after the experiment.Write an experimental report (p. 6-6)ObjectiveTo investigate the action of pepsin in protein digestion.Apparatus and materials 6 test tubes 1 test tube rack1 measuring cylinder (10 cm 3) 1 knife1 water bath dilute hydrochloric aciddilute sodium carbonate solution distilled water pepsin solution 1 hard-boiled eggProcedure 1 Cut the egg white of the hard-boiled egg into six small cubes of length 0.5 cm and put one in each of the six test tubes.2Add the following solutions to the test tubes.4Observe and note any changes in the size and appearance of the egg white cube in each testtube.ResultsAnalysis and discussion 1 Stomach. 2 Protease. 3 Peptides.4 Positive. Pepsin is a protein and it changes the colour of the Albustix paper. 5(Answer varies with the design.)ConclusionPepsin digests proteins in an acidic medium.Practical 6.3 Demonstration of the effect of bile salts on oil Results (p. 6-10)Question (p. 6-10)Water cannot break down oil into small droplets as the bile salt solution does. Therefore, no emulsion is formed and two layers of liquids can be seen.Conclusion (p. 6-10)Bile salts can break down lipids into small droplets. It is an emulsifying agent.Practical 6.4 Simulation of digestion and absorption in the small intestine using dialysis tubing(p. 6-12)Questions (p. 6-12)1 Starch solution on the outside of the tubing will affect the result. Washing the tubingensures no such starch solution is present.2 Less water allows a higher concentration of starch or reducing sugar molecules for easydetection.New Senior Secondary Mastering Biology Book 1A Practical workbook answer p.31/314 a Reducing sugar (maltose) is found.b Amylase digests starch into maltose. Maltose molecules are small enough to passthrough the tubing and diffuse into the water outside the tubing, whereas the largestarch molecules are retained inside the tubing.5 Through digestion, food substances are broken down into small molecules that can diffusethrough the intestinal wall / epithelium into the blood for use in our body.6 Maltose molecules are not small enough to pass through the small intestine.The small intestine can absorb digested food by active transport but the dialysis tubing cannot.The small intestine can secrete enzymes but the model cannot.The small intestine shows peristalsis but the model does not.There are many types of food molecules in the small intestine apart from starch.The food molecules have to pass through more than one layer of cells instead of only one layer of tubing.The blood is enclosed in blood vessels.7 Diffusion rate of the reducing sugar molecules can be increased by stirring the surroundingwater and using a water bath at a higher temperature.More concentrated solutions of starch and amylase can be used to speed up the reaction rate.Oxford University Press 2009。