計算機英語實用教程Unit7

1、unit 7 network【教學目的】o learn about the english terms of network: lan （局域網）,wan （廣域網）,band （波 段）,bandwidth （帶寬）,bridge （網橋）,repeater （轉發(fā)器）,router （路由器）,full duplex （全雙工）,optical fiber （光纖），packet （數據包）,star network （星型網絡）,switch （交換機）,hub （集線器）,tp, “twisted pair” （雙絞線）o improve the students * ability

2、to understand the long and difficult sentences in the text.o master the key language points and grammatical structures in the text.o consolidate the technical terms and important professional phrases by doing exercises.【教學重點難點】olmportant technical terms:lan （局域網），wan （廣域網），band （波段）,bandwidth （帶寬）,b

3、ridge （網橋）， repeater （轉發(fā)器）,router （路由器）,full duplex （全雙工），optical fiber （光纖）,packet （數 據包），star network （星型網絡），switch （交換機），hub （集線器），tp, “twisted pair”（雙 絞線）o difficult sentences:1. optical input is converted to electrical form to restore a clean signal, which drives lasers that fully restores the

4、optical signal at the original signal strength.2 the twists are important: they give it electrical characteristics which allow some kinds of communications otherwise not possibleo review the important points of essential englishforward vtbuffer vt.characterize vt.【教學步驟】step oneread and explain text

5、a to the students and ask the students to keep in mind the following professional terms:network （網纟各）:a group of computers working together; the physical wire etc. connecting the computerslan （局域網）：local area networkwan （廣域網）： wide area networkband （波段）: a range of frequencies between two defined li

6、mits.bandwidth （帶寬）: a measure of capacity of information-carrying capacity on a communications channel.bridge （網橋）：a data communications device that connects two or more network segments and forwards packets between them.repeater （車專發(fā)器）：1. equipment that receives a low-power signal, possibly conver

7、ting it from light to electrical form, amplifying it or retiming and reconstructing it for transmission. 2. an optoelectrical device used at each end and occasionally intermediate points of exceptionally long fiber optic span.router （路由器）: a network device that connects two similar networks having t

8、he same network protocol.full duplex （全雙工）:the simultaneous transmission of data in both directions, used when communicating between two computers.optical fiber （）匕纖）:thin filaments of glass through which light beams are transmitted.packet （數據包）: generic term for a bundle of data，organized in a spec

9、ific way for transmissio n.bus network （總、線網纟各）: a type of network configuration where multiple nodes share access at the physical level.star network （星型網絡）:the descriptive name of any network which is configured with many branches attaching to a common point.switch （交換機）:a device that turns current

10、 on and off. a switch is a network hub device creating a direct connection to the destination port.hub （集線器）:the center of a star-type network is called a hub.tp, "twisted pair” （雙絞線）:the type of wire used by the phone company to wire telephonesstep twohelp the students to analyze the following

11、 long difficult sentences:1. optical input is converted to electrical form to restore a clean signal, which drives lasers that fully restore the optical signal at the original signal strength.optical input "光輸入”；is converted to "被轉換為 ”；electrical form “ 電格式"；to restore a clean signal,

12、 “恢復成清晰信號"。第一個定語從句關系代詞which代表electrical form；第 二個定語從句關系代詞that代表laserso全句參考譯文：“光輸入可以轉換為電格式以恢復為 清晰的信號。這個信號能夠驅動激光完全恢復光信號的原來的信號強度”。2. it（twistcd pair） has two conductors, which arc twisted. the twists arc important: they give it electrical characteristics which allow some kinds of communications, o

13、therwise not possible.雙絞線由兩根導線，它們是相絞的。相絞是重要的，這能使雙絞線具有電特性，正是電 特性可以進行某些通訊，不相絞則不行。step threereview the important idioms of essential englishforward vt.學牛-們熟悉的是forward作adv.或adj.表示方向：she leaned forward to whisper something in my ear."她傾過來跟我咬耳朵"； forward motion/movcmcnt “向前運動”。表示未來：i always look

14、 forward, not back. “我總面向未來，不想過去” ；forward planning/thinking “未來的計劃/超前的思維”。表示進步：this is a big step forward for democracy. “這是向民主發(fā)展的重要一步”。作為vt.常用于send a lcttcr/an email,尤其是繼發(fā)，如從舊地址發(fā)到新地址，把收到的信 再轉發(fā)給別人，請看例句：i'll forward any mail to your new address. “我會把所有的信件發(fā)到你的新的地址的”。i'll forward his email to

15、you if you're interested. “如果你冇興趣我就把他的 emai 轉發(fā)給 你”。本文在解釋 bridge （網橋）時是這樣說的：a data communications device that connects two or more network segments and forwards packets between them."網橋是一種數據通訊設備， 它把兩個或更多的網絡片斷連接起來使得信息包在這些網絡間可以傳送”。buffer vt.buffer作名詞"緩沖器”應該是學生們熟悉的，英語解釋為part of the memory

16、used to store data temporarily while it is waiting to be used. for example, a program might store data in a printer buffer until the printer is ready to print it.內存屮等待啟用臨時存放數據的部分，例如打 印緩沖器里可以臨時存放打印程序，直到打印機準備好打印為止。作為vt.表示"緩沖"，如本文中對bridge（網橋）的定義:it（bridgc） also amplifies the carrier signal, a

17、nd accepts data packets, （perhaps buffering them during periods of network congestion） and forwards them.它也可以放大載波信號、接收數據包（或許在網絡堵塞期實現緩沖）及 在緩沖后繼續(xù)發(fā)送數據。characterize vt. describe something by stating its main qualities 漢語譯成"表現的特色”。有 兩種用法：1. 把描寫特色的名詞作主語，如：bright colours and bold strokes characterize

18、his early paintings."他早年美術作品的特色是顏色明亮，筆畫粗壯”。2. characterize.as 把特色描述為，認為的特色是，in: in her essay, she characterizes the whole era as a period of radical change."在評論屮，她認為整個時代充滿著激進變革 時期的特點”。本文的例句屬于第一種用法，翻譯時要使用詞性轉換技巧，即把characterize動詞性翻 譯成名詞"特色”或"特點 ”:enormous capacity, low-cost, low-pow

19、er consumption, small space, lightweight, insensitivity to electromagnetic interference characterize this transport media（optical fiber）. “這種傳輸介質（光纖）的特點是容量大、價格低、功耗低、空間小、 重量輕及對電磁干擾不敏感”。step fourtext b難句解析1. technology based on thin filaments of glass or other transparent materials used as the medium

20、for transmitting coded light pulses that represent data, image and sound.本句是對fiber optics （纖維光學）的解釋。based on的意思是"基于”，thin filaments of glass 是"細的玻璃絲”，coded light pulses"編碼的光脈沖”,that represent data, image and sound 是一個定語從句，修飾和限定coded light pulseso2. a type of fiber optic cable in which there is only one mode for the light to follow, thereby minimizing dispersion (smearing in the time domain).本句是對single-mode fiber (單模光纖)的解釋。fiber optic cable的意思是"光纖電纜", in which there is only