機(jī)械專業(yè)英語(yǔ)21~24章

1、lesson 21: introduction to automobilen 詞匯講解n 課文分析n 練習(xí)答案本課教學(xué)目標(biāo)：1. 理解汽車差速器、燃油噴射器的作用；2. 掌握與汽車相關(guān)的專業(yè)詞匯；3. 熟悉獨(dú)立主格、伴隨壯語(yǔ)等語(yǔ)法現(xiàn)象。section ： words and phases1. 重點(diǎn)專業(yè)名詞解析2. 詞性轉(zhuǎn)換3. 專有名詞的通用含義4. now you will have 5 minutes to skim over the new words and phrases, marking the special words you cant understand. 1. 重點(diǎn)專業(yè)名

2、詞解析n differential n suspension n transmission n driving axle & driving shaft differentialn 汽車發(fā)動(dòng)機(jī)的動(dòng)力經(jīng)離合器、變速器、傳動(dòng)軸，最后傳送到驅(qū)動(dòng)橋再左右分配給半軸驅(qū)動(dòng)車輪，在這條動(dòng)力傳送途徑上，驅(qū)動(dòng)橋是最后一個(gè)總成，它的主要部件是減速器和差速器。減速器的作用就是減速增矩，這個(gè)功能完全靠齒輪與齒輪之間的嚙合完成，比較容易理解。而差速器就比較難理解，什么叫差速器，為什么要“差速”？n 汽車差速器是驅(qū)動(dòng)轎的主件。它的作用就是在向兩邊半軸傳遞動(dòng)力的同時(shí)，允許兩邊半軸以不同的轉(zhuǎn)速旋轉(zhuǎn)，滿足兩邊車輪盡可能

3、以純滾動(dòng)的形式作不等距行駛，減少輪胎與地面的摩擦。 suspensionn 車身好比是人的上半身,輪胎好比是人的腳,懸掛系統(tǒng)就好比是人的腿。n 汽車懸架包括彈性元件，減振器和傳力裝置等三部分，這三部分分別起緩沖，減振和力的傳遞作用。transmissionn 發(fā)動(dòng)機(jī)的輸出轉(zhuǎn)速非常高，最大功率及最大扭矩在一定的轉(zhuǎn)速區(qū)出現(xiàn)。為了發(fā)揮發(fā)動(dòng)機(jī)的最佳性能，就必須有一套變速裝置，來(lái)協(xié)調(diào)發(fā)動(dòng)機(jī)的轉(zhuǎn)速和車輪的實(shí)際行駛速度。變速器可以在汽車行駛過(guò)程中，在發(fā)動(dòng)機(jī)和車輪之間產(chǎn)生不同的變速比，通過(guò)換擋可以使發(fā)動(dòng)機(jī)工作在其最佳的動(dòng)力性能狀態(tài)下。變速器的發(fā)展趨勢(shì)是越來(lái)越復(fù)雜，自動(dòng)化程度也越來(lái)越高，自動(dòng)變速器將是未來(lái)的主流

4、。driving axle & driving shaft n 驅(qū)動(dòng)橋處于動(dòng)力傳動(dòng)系的末端，其基本功能是增大由傳動(dòng)軸或變速器傳來(lái)的轉(zhuǎn)矩，并將動(dòng)力合理的分配給左、右驅(qū)動(dòng)輪，另外還承受作用于路面和車架或車身之間的垂直立、縱向力和橫向力。驅(qū)動(dòng)橋一般由主減速器、差速器、車輪傳動(dòng)裝置和驅(qū)動(dòng)橋殼等組成。2. 詞性轉(zhuǎn)換n ignition n ignite vt 點(diǎn)燃；激起 vi 著火n lubrication n lubricate vt 使?jié)櫥?vi 起潤(rùn)滑作用n cylinder n cylindrical adj 圓柱形的n intermittent adj intermission n 間

5、歇，休息時(shí)間； intermittence n 斷續(xù)性，周期性n compensate v compensation n補(bǔ)償 ，補(bǔ)償金 ，報(bào)酬 q did you get any compensation when you were dismissed from your job?q the job is hard but the compensation is good.3. 專業(yè)名詞的通用含義n differential n 差別，差速器；adj 差別的n muffler n 消聲器，圍巾，厚手套n tire n 輪胎；vt 使疲勞；vi 疲勞，厭煩（+of）q she never tir

6、es of talking about her hometown.n transmission n 變速器，傳送，傳播q the transmission of diseasesn manifold n 多種，管；adj 種種的q manifold dutiesn now please read the new words after me for 2 times.n after that, you will have 10 minutes to remember as many words as you can.section ： textn at first, read the first

7、 paragraph silently in two minutes, please.paragraph :n automobile（fig.6.1） is a self-propelled vehicle used for travel on land. the term is commonly applied to a four-wheeled vehicle designed to carry two to six passengers and a limited amount of cargo, as contrasted with (與.比較) a truck, which is d

8、esigned primarily for the transportation of goods and is constructed with larger and heavier parts, or a bus (or omnibus or coach), which is a large public conveyance designed to carry a large number of passengers and sometimes additionally small amounts of cargo.n 一般來(lái)說(shuō)，汽車是指陸地上行駛的機(jī)動(dòng)式車輛，具有四個(gè)輪子，用來(lái)搭載兩至

9、六名乘客和少量貨物。我們可以把它與卡車或公汽對(duì)比一下，卡車的零部件更大更重，主要用來(lái)運(yùn)輸貨物；公共汽車(或公共馬車、長(zhǎng)途汽車)是一種大型的公共運(yùn)輸工具，用來(lái)搭載大量的乘客，有時(shí)也附加地運(yùn)輸少量的貨物。 oral english practice :n please describe the functions of an automobile, a truck and a bus separately!n read the second paragraph silently in two minutes, please.paragraph :n differential, fuel injec

10、tion, ignition, internal-combustion engine, lubrication, muffler, odometer, shock absorber, speedometer, steering system, suspension, tachometer, tire and transmission are the main operation and technical features of automobiles.n 差速器、燃油噴射器、點(diǎn)火器、內(nèi)燃機(jī)、潤(rùn)滑裝置、消聲器、里程表、減震器、速度計(jì)、駕駛裝置、懸掛、轉(zhuǎn)速計(jì)、輪胎和變速器反應(yīng)了小汽車的主要操作特

11、性和技術(shù)特性。paragraph :n differential and fuel injection system are introduced in this lesson, with other components presented in the following lessons.n 本課介紹了差速器和燃油噴射系統(tǒng)，其他零部件將在后續(xù)幾課中介紹。獨(dú)立主格結(jié)構(gòu)（一）： 獨(dú)立主格結(jié)構(gòu)的構(gòu)成： 名詞(代詞)+現(xiàn)在分詞、過(guò)去分詞；名詞(代詞)+形容詞；名詞(代詞)+副詞；名詞(代詞)+不定式；名詞(代詞) +介詞短語(yǔ)構(gòu)成。（二） 獨(dú)立主格結(jié)構(gòu)的特點(diǎn)：1）獨(dú)立主格結(jié)構(gòu)的邏輯主語(yǔ)與句子的主語(yǔ)不

12、同，它獨(dú)立存在。2）名詞或代詞與后面的分詞，形容詞，副詞，不定 式，介詞等是主謂關(guān)系。3）獨(dú)立主格結(jié)構(gòu)一般有逗號(hào)與主句分開。n the test finished, we began our holiday.= when the test was finished, we began our holiday.考試結(jié)束了，我們開始放假。the president assassinated, the whole country was in deep sorrow.= after the president was assassinated, the whole country was in de

13、ep sorrow.總統(tǒng)被謀殺了，舉國(guó)上下沉浸在悲哀之中。weather permitting, we are going to visit you tomorrow.如果天氣允許，我們明天去看你。this done, we went home.工作完成后，我們才回家。the meeting gone over, everyone tired to go home earlier.會(huì)議結(jié)束后，每個(gè)人都想早點(diǎn)回家。he came into the room, his ears red with cold.他回到了房子里，耳朵凍壞了。he came out of the library, a la

14、rge book under his arm.他夾著本厚書，走出了圖書館。n now well come to paragraph four, the most difficult one in this passage, please read the it silently in 5 minutes,.paragraph :n differential in the automobile is a set of gears used on the driving axle. the two wheels on the driving axle must be interconnected

15、in order to receive their energy from the same source, the driving shaft; at the same time they must be free to revolve at different speeds when necessary (e.g., when rounding a curve, the outer wheel travels farther and thus must revolve faster than the inner wheel in order to prevent skidding).n 汽

16、車差速器由裝在驅(qū)動(dòng)橋上的一套的齒輪組成。驅(qū)動(dòng)橋兩端的車輪必須互連，以便從同一個(gè)動(dòng)力源即傳動(dòng)軸上獲取能量；同時(shí)，必要時(shí)，兩個(gè)車輪必須能自由地以不同的速度旋轉(zhuǎn)（例如，拐彎時(shí)，外側(cè)的輪子比內(nèi)側(cè)的行駛的距離更遠(yuǎn)，為了避免打滑，故其轉(zhuǎn)速應(yīng)更快）。 n these two requirements are met by the differential gearing. furthermore, through it the rotating motion of the driving shaft is transmitted to the axle and the wheels. the axle is

17、 in two halves; to each half is attached a wheel at one end and, at the inner end, a gear. the end of the driving shaft is also equipped with a gear. by an ingenious arrangement (fig.6.2) of these and other gears, together constituting the differential, a difference in speed of the two wheels is com

18、pensated for without a loss of tractive force. n 使用差動(dòng)傳動(dòng)裝置能同時(shí)滿足這兩個(gè)要求。此外,通過(guò)差速傳動(dòng)裝置可以把傳動(dòng)軸的旋轉(zhuǎn)運(yùn)動(dòng)傳遞給驅(qū)動(dòng)軸和車輪。驅(qū)動(dòng)軸由兩個(gè)半軸組成；每個(gè)半軸外端裝了一個(gè)車輪，內(nèi)端裝了了一個(gè)(半軸)齒輪。傳動(dòng)軸的一端也裝了一個(gè)齒輪。通過(guò)精巧地布置上述和其他的一些齒輪組成差速器，兩個(gè)車輪的速度差異就能得到補(bǔ)償，且不損失牽引力。 n 左側(cè)大圖表示其基本結(jié)構(gòu)。n 右上圖表示2側(cè)半軸同步轉(zhuǎn)動(dòng)時(shí)，行星齒輪不轉(zhuǎn)，而帶著兩側(cè)半軸同步轉(zhuǎn)動(dòng)。n 右下圖表示當(dāng)右側(cè)半軸轉(zhuǎn)速超過(guò)左側(cè)半軸時(shí)，其極端情況是左半軸停止轉(zhuǎn)動(dòng)時(shí)，由于傳動(dòng)軸強(qiáng)迫盆齒以一定的

19、速度繼續(xù)轉(zhuǎn)動(dòng)，2個(gè)行星齒輪便會(huì)產(chǎn)生左右相反的轉(zhuǎn)動(dòng)，而該轉(zhuǎn)動(dòng)又會(huì)使右側(cè)半軸在原來(lái)跟隨盆齒轉(zhuǎn)動(dòng)的基礎(chǔ)上又產(chǎn)生一個(gè)向前的轉(zhuǎn)動(dòng)量。這時(shí)右半軸的轉(zhuǎn)速來(lái)自于兩部分原因：第一，盆齒的轉(zhuǎn)動(dòng)，第二，行星齒輪的轉(zhuǎn)動(dòng)。因此，行星齒輪組轉(zhuǎn)動(dòng)的結(jié)果相當(dāng)于把不轉(zhuǎn)動(dòng)或轉(zhuǎn)動(dòng)慢的一側(cè)半軸的轉(zhuǎn)速傳遞給了另一側(cè)半軸。所以，當(dāng)盆齒轉(zhuǎn)動(dòng)速度一定的時(shí)候，兩側(cè)半軸的轉(zhuǎn)速和是一個(gè)定值，而差速器的作用就是在這個(gè)前提下，使左右半軸的速度可以自由分配。 n 常見(jiàn)的差速器的缺點(diǎn)是：當(dāng)一個(gè)車輪走在干硬的地面上而另一個(gè)車輪走在濕滑的地面上時(shí)，差速器會(huì)導(dǎo)致走在打滑地面上的輪子轉(zhuǎn)速加倍，而使另外一個(gè)輪子保持靜止。使用防滑差速器則能避免出現(xiàn)這一危險(xiǎn)情況，這種

20、分速器在某個(gè)車輪開始打滑時(shí)只給另一個(gè)車輪供給能量，從而保持汽車移動(dòng)。 oral english practice :n is a differential a part of driving axle? and whats its function?n do driving axle and driving shaft refer to the same thing? if not, whats the difference between them?n now we will come to the last paragraph, read it silently in 5 minutes,

21、 please!paragraph :n fuel injection system in an internal-combustion engine delivers fuel or a fuel-air mixture to the cylinders by means of pressure from a pump. it was originally used in diesel engines because of diesel fuel's greater viscosity and the need to overcome the high pressure of the

22、 compressed air in the cylinders. a diesel fuel injector sprays an intermittent, timed, metered quantity of fuel into a cylinder, distributing the fuel throughout the air within.n 內(nèi)燃機(jī)上的燃油噴射系統(tǒng)通過(guò)泵產(chǎn)生的壓力來(lái)將油或油氣混合物傳遞給汽缸。燃油噴射系統(tǒng)最早用在柴油機(jī)上，因?yàn)椴裼偷酿ざ容^大,且需克服汽缸里受壓縮空氣的高壓。柴油噴射器間歇地、定時(shí)地將一定量的柴油噴灑到汽缸中，使燃油與空氣充分混合。 n fuel

23、injection is also now used in gasoline engines in place of a carburetor. in gasoline engines the fuel usually is injected into the intake manifold and mixed with air, and the resulting mixture is delivered to the cylinder. modern fuel injection systems use computers to regulate the process. fuel inj

24、ection results in more efficient fuel combustion, improving fuel economy and engine performance and reducing polluting exhaust emissions. oral english practice :n fuel injection system can be used both in diesel engine and gasoline engine, however, is there any difference between them?section ： exer

25、cisesn now its time to do the exercises. and please finish them in five minutes.n this is the end for lesson 21.n it will be pretty good if you could review lesson 21 and preview lesson 22 in your spare time.lesson 22 internal combustion enginen 詞匯講解n 課文分析n 練習(xí)答案本課教學(xué)目標(biāo)：1. 掌握內(nèi)燃機(jī)的分類方法；2. 掌握與內(nèi)燃機(jī)相關(guān)的專業(yè)詞匯；

26、3. 翻譯技巧：信*達(dá)*雅section ： words and phasesn see if you can pronounce these words rightly:q exothermic 9eksejw:mik adj. 化發(fā)熱的q petroleum pi5treuliem n. 石油 q turbocharge t:bejtfb:dv vt. 用渦輪給(發(fā)動(dòng)機(jī))增壓 n pay close attention to the words concerning an internal combustion engineq pistonq rotorq connecting rodq

27、cylindern now please remember the new words and phrases as fast as you can. section ： textn at first, read the first paragraph silently in 3 minutes, please.paragraph :n the internal combustion engine is a heat engine in which the burning of a fuel occurs in a confined space called a combustion cham

28、ber. this exothermic reaction of a fuel with an oxidizer creates gases of high temperature and pressure, which are permitted to expand. the defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause movement, for example by

29、acting on pistons, rotors, or even by pressing on and moving the entire engine itself.n 內(nèi)燃機(jī)是一種熱機(jī)，燃料在其被稱為燃燒室的密封空間內(nèi)燃燒。燃料和氧化劑間的放熱反應(yīng)產(chǎn)生可膨脹的高溫高壓氣體。內(nèi)燃機(jī)的顯著特點(diǎn)是能做有用功，即膨脹的受熱氣體直接作用在物體上并使其運(yùn)動(dòng)，如活塞、轉(zhuǎn)子，乃至整個(gè)內(nèi)燃機(jī)本身。oral english practice :n whats an internal combustion engine?n say whats you know about an internal combu

30、stion engine as much as you can.n read the second paragraph silently in two minutes, please.paragraph :n car engines vary in design, but certain elements are common to all engines and are used for engine classification. engines can be classified in several ways such as the number of cylinders, the g

31、eometry of the block, or type of ignition system used. the two major engine types in use are spark ignition (gasoline engine) and compression ignition (diesel engine) which use different types of fuel. the following are ways engines are classified.n 汽車內(nèi)燃機(jī)因設(shè)計(jì)的不同而不同，但某些元件是所有內(nèi)燃機(jī)所共有的，并用作內(nèi)燃機(jī)的分類依據(jù)。內(nèi)燃機(jī)可按氣缸

32、的數(shù)目、氣缸的排列方式和點(diǎn)火系統(tǒng)的類型等方式分類。常用的兩大類內(nèi)燃機(jī)是火花點(diǎn)火式（汽油機(jī)）和壓縮點(diǎn)火式（柴油機(jī)）內(nèi)燃機(jī)，他們使用不同種類的燃料。下面是內(nèi)燃機(jī)的分類方法。 oral english practice :n in how many ways can engines be classified? and what are they?n flip through the third paragraph in two minutes, please.paragraph :n fuel burned:n fuel burned provides a broad engine classif

33、ication. two types of fuel are in general use: gasoline and diesel oil. gasoline car engines use spark ignition whereas diesel engines use compression ignition (no spark.) alternate fuels such as liquefied petroleum gas (lp-gas), gasohol (90% gasoline, 10% alcohol), and pure alcohol are used in very

34、 limited situations.n 按所用燃料分類是使用的較為廣泛的一種分類方法。汽油和柴油是使用的最為廣泛的兩種燃料。汽油機(jī)采用火花點(diǎn)火而柴油機(jī)采用壓縮點(diǎn)火（無(wú)火花）。諸如石油液化氣、酒精-汽油混合燃料（90汽油，10酒精）和純酒精等代用燃料使用地較少。 oral english practice :n how many kinds of fuel can be in use in internal combustion engines according to paragraph 3? and what are they?n now well come to paragraph f

35、our, please read the it silently in 3 minutes,.paragraph :n block geometry:n there are four types of engine block geometry: v-type, inline, horizontally opposed and slant. each refers to the orientation of the cylinders as viewed from the front or back of the engine. a v-type has two angled rows of

36、cylinders, which form a “v.” an inline engine arranges the cylinders vertically in a row. the horizontally opposed engine has the cylinders horizontal and opposing each other. a slant design is one row of angled cylinders forming a half “v.” a slant block allows the hood line to be lower. n 氣缸有四種排列方

37、式：v型、立式、臥式對(duì)置和傾斜布置。每一種方式是指氣缸從內(nèi)燃機(jī)的前面或后面看上去的方位。v型是指氣缸排成類似v型的兩排。立式內(nèi)燃機(jī)的多個(gè)氣缸垂直排成一排。臥式對(duì)置內(nèi)燃機(jī)的氣缸水平對(duì)置。傾斜式內(nèi)燃機(jī)的氣缸排成類似半個(gè)v型的一排。傾斜式內(nèi)燃機(jī)的車篷可以設(shè)計(jì)的更低。 n now browse paragraph five in 3 minutes, please.paragraph :n number of cylinders:n the number of cylinders is often used in combination with the engine block geometry (

38、v6, slant four, inline four.) the number of cylinders is an indication of how smooth the car engine will run. an eight-cylinder engine will run smoother than a four-cylinder engine since power strokes occur with greater frequency. the number of cylinders also contributes to power output; more cylind

39、ers, more power. however, this is not always a good indicator of power output. a turbocharged, four-cylinder engine can produce more power than a normally aspirated six-cylinder engine. n 氣缸數(shù)目分類法常常與氣缸排列方式分類法聯(lián)合使用（如v型6缸、傾斜型4缸和立式4缸）。氣缸的數(shù)目可以指示出汽車發(fā)動(dòng)機(jī)運(yùn)行的平穩(wěn)性。8缸內(nèi)燃機(jī)比4缸內(nèi)燃機(jī)的工作沖程間隔短，故運(yùn)行更平穩(wěn)。氣缸的數(shù)目還與輸出功率有關(guān)，氣缸越多，內(nèi)燃

40、機(jī)輸出的功率就越大，但這也不是絕對(duì)的。一個(gè)渦輪增壓4缸發(fā)動(dòng)機(jī)有可能比通常的吸氣式的6缸發(fā)動(dòng)機(jī)輸出的功率還大。n now please have a glance at paragraph six in 2 minutes.paragraph :n ignition type:n two methods for igniting fuel are used, spark ignition and compression ignition. gasoline car engines use spark ignition whereas diesel engines use compression

41、ignition. this method compresses the air to the point where the resulting rise in temperature causes ignition to occur when diesel fuel is added.n 按點(diǎn)火方式可分為兩種：火花點(diǎn)火和壓縮點(diǎn)火。汽油機(jī)使用火花點(diǎn)火，而柴油機(jī)使用壓縮點(diǎn)火。壓縮點(diǎn)火方式是指添加柴油時(shí)壓縮空氣使溫度升高到柴油的燃點(diǎn)而使柴油燃燒。section ： exercisesn now its time to do the exercises. and please finish the

42、m in five minutes.n this is the end for lesson 22.n it will be greatly appreciated if you could review lesson 21&22 and preview lesson 23 in your leisure time.lesson 23 manual transmission in automobilen 詞匯講解n 課文分析n 練習(xí)答案本課教學(xué)目標(biāo)：1. 了解什么是手動(dòng)變速器；2. 掌握與變速器相關(guān)的專業(yè)詞匯。section ： words and phasesn having a g

43、lance at the new words table, youll find every word is very professional.n how to remember these words and phrases rapidly?q there is no short-cut. q the only way is “more practice”.n check if you have remembered all the words or not with the help of your deskmate.section ： textn at first, read the

44、first paragraph silently in 3 minutes, please.paragraph :n a manual transmission (also known as a stick shift, or standard transmission) is a type of transmission used in automotive applications. manual transmissions often feature a driver-operated clutch and a movable gear selector, although some d

45、o not. most automobile manual transmissions allow the driver to select any gear at any time, but some, such as those commonly mounted on motorcycles and some types of racing cars, only allow the driver to select the next-highest or next-lowest gear ratio. this second type of transmission is sometime

46、s called a sequential manual transmission.n 手動(dòng)變速器(亦作變速桿和標(biāo)準(zhǔn)變速器)是汽車駕駛時(shí)應(yīng)用的一種變速器.手動(dòng)變速器通常以司機(jī)可操縱的離合器、可動(dòng)的檔位選擇器為特征,然而也不盡然.大多數(shù)的汽車手動(dòng)變速器允許司機(jī)隨意選擇任何檔位,但某些手動(dòng)變速器,如那些一般裝在摩托車和某些種類的賽車上的,就只允許司機(jī)選擇相臨檔位的齒數(shù)比。后一種的變速器有時(shí)也被稱為順序手動(dòng)變速器。oral english practice :n ask your deskmate a question according to the first paragraph.n read

47、the second paragraph silently in two minutes, please.paragraph :n manual transmissions are characterized by gear ratios that are selectable by engaging pairs of gears inside the transmission. conversely, automatic transmissions feature clutch packs to select gear ratio. transmissions that employ clu

48、tch packs but allow the driver to manually select the current gear are called semi-automatic transmissions.n 手動(dòng)變速器的特征參數(shù)為傳動(dòng)比, 通過(guò)選擇變速器內(nèi)部的嚙合齒輪對(duì)可選擇傳動(dòng)比.相反地,自動(dòng)變速器的特點(diǎn)是利用離合器箱來(lái)選擇傳動(dòng)比.既能實(shí)現(xiàn)自動(dòng)變速又能實(shí)現(xiàn)手動(dòng)變速的變速器叫做半自動(dòng)變速器。oral english practice :n ask your deskmate a question according to the second paragraph.n flip thr

49、ough the third paragraph in two minutes, please.paragraph :n contemporary automotive manual transmissions are generally available with four to six forward gears and one reverse gear, although manual transmissions have been built with as few as 2 and as many as 7 gears. some manuals are referred to b

50、y the number of forward gears they offer (e.g., 5-speed) as a way of distinguishing between automatic or other available manual transmissions. similarly, a 5-speed automatic transmission is referred to as a 5-speed automatic.n 手動(dòng)變速器可有二至七個(gè)檔位，但當(dāng)代的汽車手動(dòng)變速器通常采用四至六個(gè)前進(jìn)檔和一個(gè)倒檔. 手動(dòng)變速器根據(jù)前進(jìn)檔的個(gè)數(shù)來(lái)命名(如5檔),以區(qū)分自動(dòng)變速器

51、和其他的手動(dòng)變速器.類似的,5檔自動(dòng)變速器被簡(jiǎn)稱為5檔自動(dòng).oral english practice :n one student stand up to ask a question according to the third paragraph.n another give an answer.n now well come to paragraph four and five, please read the it silently in 2 minutes,.paragraph :n other types of transmission in mainstream automot

52、ive use are the automatic transmission, semi-automatic transmission, and the continuously variable transmission7.n 主流汽車上使用的其它類型變速器有自動(dòng)變速器、半自動(dòng)變速器和無(wú)級(jí)變速器。 paragraph :n the image（fig.6.4） below shows the most common five-speed layout found in the usa and the uk.n 下圖所示為美國(guó)和英國(guó)最常見(jiàn)的5檔變速器的布局.n now browse parag

53、raph six in 2 minutes, please.paragraph :n this layout is reasonably intuitive because it starts at the upper left and works top to bottom, left to right, with reverse far away and toward the rear of the car. there is usually a mechanism that only allows selection of reverse from the neutral positio

54、n, so reverse will be less likely to be accidentally chosen when downshifting from 5th to 4th (or by someone used to a 6-speed transmission and trying to shift from 5th to the non-existent 6th).n 這種布局顯然是合理的,因?yàn)樵摬季謴淖笊辖情_始,自上而下,自左而右,退檔布置在汽車后部,不易誤操作.還有一種常用的結(jié)構(gòu)是從空擋位置選擇退檔,這樣就盡可能避免在從5檔換到4檔的時(shí)候錯(cuò)選了退檔(或被一個(gè)用慣了6級(jí)變

55、速器的人從5檔換到并不存在的6檔)oral english practice :n one student ask a question according to the sixth paragraph.n another give an answer.n now please have a glance at paragraph seven in 2 minutes.paragraph :n manual transmissions typically offer better fuel economy than automatics. increased fuel economy with

56、 a properly operated manual transmission vehicle versus an equivalent automatic transmission vehicle can range from 5% to about 15% depending on driving conditions and style of driving - extra urban or urban (highway or city).n 手動(dòng)變速器通常比自動(dòng)變速器有更好的節(jié)油性.依行車條件和駕駛風(fēng)格的不同(郊區(qū)或城區(qū),路況),手動(dòng)變速器汽車比同規(guī)格的自動(dòng)變速器汽車節(jié)油5%到15%

57、。oral english practice :n one student ask a question according to the seventh paragraph.n another give an answer.n now please have a glance at paragraph eight in 2 minutes.paragraph :n maintenance of manual transmissions:n because clutches use changes in friction to modulate the transfer of torque between engine and transmission（fig.6.5）, they are subject to wear10 in everyday use. a very good clutch, when used by an expert driver, can last hund