初三英语第三单元课件(共8篇)
一、教学目标:
1. 语言知识目标
基本词汇:milk, cow, horse, feed, farmer, quite, anything, grow, farm, pick,
excellent, coutryside, yesterday, flower, worry, luckily, sun, museum,
fire, painting, exciting, lovely, expensive, cheap, slow, fast, robot,
guide, gift, everything, interested, dark, hear
基本词组:milk a cow, ride a horse, feed chickens, quite a lot (of…), in the
countryside, fire station, all in all, be interested in
基本句型:How was your school trip ? It was great !
Did you go to the zoo ? No, I didn’t. I went to a farm.
Did you see any cows ? Yes, I did. I saw quite a lot.
Did Carol ride a horse ? No, she didn’t. But she milked a cow.
Were the strawberries good ? Yes, they were . No, they weren’t.
2. 技能目标: 能运用一般过去时描写过去的事情
3. 情感目标: 学会客观地表达对事物的看法,培养乐观向上的性格
二、 教学重难点:
1. 教学重点:一般过去时的判断及选用
2. 教学难点:正确运用一般过去时
三、教学步骤:
Period 1
Section A (1a-2d)
Step 1 : Warming –up
1 Greeting
Who is on duty today ?
Who was on duty yesterday ?
What is the weather like today ?
What was the weather like yesterday ?
2 Song : Play the song “ Old MacDonald had a farm” and have Ss find out the animals in the song
Get Ss answer like this : On the farm ,there are some ducks, cats,chickens, cowspigs,dogs and horses . They are animals.
Step 2 : Presentation
1 Show a picture and tell Ss: This is also a farm. Last week Carol and his classmates had a school trip. They went to the farm. What did they do on the farm? How was their school trip?
2 Show some pictures again and try to get the past tense verbs expressions according to the pictures.
(1) Show the picture and the question
(2) Ask one student to answer the question.
(3) All students read it toghter.
Q:Did he ride a horse?
A:Yes, he did. He rode a horse.
Q:Did he milk a cow?
A:Yes, he did. He milked a cow.
Q:Did he ride a horse?
A :No, he didn’t .
Did he feed chickens?
Yes, he did. He fed chickens.
Did you go to the zoo?
No, I didn’t. I went to a farm.
Did you see any cows ?
Yes, I did. I saw quite a lot.
Did they pick any strawberries on the farm ?
Yes, they did .
How were the strawberries?
They were delicious.
Were the strawberries good?
Yes, they were.
No, they weren’t.
How was your school trip ?
It was great.
Were the strawberries good ?
Yes ,they were.
No, they weren’t.
Step 3 Exercises
Step 4 : Practice (Listening and speaking)
1a Match the phrses with the pictures.
1b Listen and circle the three things Carol did on her school trip in 1a.
1c Ask and answer questions about Carol’s school trip.
2a Listen and check the questions you hear.
2b Listen again.Circle T for true or F for false
一、正确把握单元复习与总复习的勾连性
三年级作为独立的年级, 课本内容本身具有一定的独立性。每一单元都有各自的主题和语法重点, 这就对教师的教学工作提出了最基本的要求。
在单元复习的过程中首先要依据教材制定复习计划, 根据每一单元的知识侧重点设计复习课件, 组织复习训练, 有方向、有主次地引导学生掌握每一单元的重点知识点。
此外, 通过单元复习课的开展将有效地引导学生对本周所学单元的内容进行一个条理清晰、重点分明的回顾, 能够强化学生这一周以来的学习记忆, 使学生能够跟着复习课堂的指引自发地检查自己的掌握程度, 提出疑问, 巩固所学, 做到温故而知新。
例如:初三英语上册的第四单元《TV program》介绍了许多节目的英语单词及词组, 而复习最基本的要求是掌握与电视节目相关特性的英语单词和词组, 那么教师就可以通过运用含义描述使学生理解award, concert, broadcast等词汇, 以及不同TV program的性质用up-to-date, live, roundup该怎么表达。通过这样的教学, 加深学生的印象以夯实基础。
在主抓单元内容的同时, 也必须看到, 三年级的英语学习是在在一、二年级的基础上对学生的英语学习能力所做的进一步培养和拓展, 即使是单元与单元之间, 也遵守一定程度上循序渐进的规则。
一方面, 单元复习要以教材内容为基础, 另一方面也可以将它与总复习勾连起来。利用单元复习的内容帮助学生回忆相关的知识点, 在基础之上做适当地拓展延伸, 分层训练, 在考点的勾连方面能够对学生进行适当的引导。仍旧借助上述第四单元的例子来看, 本单元的基础学习虽然是“TVprogram”, 高频考察的却是与电视节目有关的时间性形容词、副词, 如:weekly, daily等词汇的理解。所以, 单元复习时就需要教师格外注意对这个知识点的强调和讲解, 多创造综合情境考察学生对上述语法的运用。
二、授课时张弛有度, 激发学生的创造力
很多教师在复习课上往往陷入一个误区, 那就是“反复训练以加深记忆”。复习往往就变成了单调的题目操练, 学生深陷在听课、训练的疲劳之中, 而收到的效果却不尽人意, 如此周而往复, 只会让学生觉得沉闷枯燥, 收效甚微。
其实, 反复训练的反复并不意味着忽视科学性。复习同样需要张弛有度, 合理科学的授课方法。针对一个知识点, 教师应该先做到深入细致地讲解, 学生在理解的基础上记忆往往会事半功倍;其次, 应该采用间歇性回顾法, 借助数个复习要点跳跃性、间歇性地出现, 触发学生的记忆开关, 不至于使学生落入思维定势的陷阱之中。
孔子早就说过要“因材施教”。学生作为获得知识的主体是每一个拥有自我意识、自主意识的个体, 并不适用无差别的被动接受式教学方法。
1.基础比较薄弱的学生;对于基础比较薄弱的学生, 教师要多一点耐心, 对有难度的语法分类讲, 分布讲, 举例讲, 给学生充分的时间去消化。例如:长句型find/think/make/keep+n/pron+adj的讲解, 可能就需要教师多补充一些例句, 对动词find/think/make/keep的性质做详细的讲解。
2.掌握知识较快的学生;对于掌握知识较快的学生, 在复习时可以尽量唤起学生的主动性, 激发学生主动回忆勾连所学的知识。
此外, 教师可以在课堂上采取竞赛问答, 小组合作, 情景对话等使同学自觉地去召唤出脑海中学过的知识点, 主动去联系、辨析他们。在学生积极地思考, 热烈地参与集体讨论的时候, 也就是课堂效果最好的时候, 教师所要做的就是从旁协助, 对表现优秀、参与积极的学生进行赞许, 在学生答错的时候善意地鼓励, 并纠正他们的错误, 多多提示和启发, 学生的兴趣和专注度提高了, 复习也就更认真, 记忆也会更深刻。
三、注重课前准备和课后回顾工作
单元复习通常是以单元复习课的形式出现的, 课堂的时间总是有限的, 但是课堂复习的任务是繁重的。为此, 笔者觉得可以采用“复习课课前预习”的方法。
教师尝试将一些知识点的准备工作放到课前预习的阶段来做, 如督促同学们养成在单元复习课前自主总结知识点、疑难点的良好习惯, 总结自己觉得重要的地方, 并圈划出自己觉得难以理解, 不善于运用的知识点, 为即将所复习的知识做一个预热。
通过这样一个预热过程, 学生不会对复习课堂上大量的知识点总结觉得陌生, 反而能够有选择、有针对性地重点解决自己觉得困难的知识点, 听课时也变得全神贯注。例如:当学到《Have you packed yet?》, have you done的完成时态, 复习无疑是课堂复习的重点。此外, that is则是一个简单的词组知识, 不需要投入太多的教学时间。
此外, 教师和学生都可以把各自总结的知识点相互参照。这一方式有利于学生主动去把握中考的考点所在, 划分学习的主次。同时, 这一方式也有利于教师更好地掌握学生的复习情况, 从而检验出教学授课方式的成效高低。
当然, 一堂复习课结束之后, 再一次的课后回顾也很有必要。这种复习课后的再回顾就是一个真正查缺补漏的精简阶段。可以由教师带领, 学生们利用一个简短的课后时间, 合上书, 各自默默回顾一遍复习课的要点, 检验自己在课前的疑难问题是否得到解答。一个单元经过这样三次反顾, 学生对这个单元的把握会变得条理分明而透彻稳固。
总而言之, 单元复习是初三教学中的不可忽视的步骤, 值得教师去开辟不同的途径, 尝试灵活的方法为学生创造一个自主灵动、有趣有效的复习环境。
摘要:初三是整个初中英语教学过程的最后阶段, 单元复习则是初三教学过程的阶段性积累, 是初三英语总复习的前奏和伏笔。单元复习有助于学生加强对知识的理解, 提高记忆能力, 从而更好地迎战中考。在下文中, 笔者根据日常的教学经验对如何提高单元复习效率总结了一些自己的看法。
关键词:九年级英语,单元复习,教学方法
参考文献
[1]杨培风.初中英语中考复习策略研究[J].教育教学论坛, 2011年10月.
[2]梁慧敏.初三英语复习课模式初探[J].科学大众 (科学教育) , 2012年2月.
“在追梦路上繁花似锦。”
——题记
“我们都是追梦人……”熟悉的旋律又在耳畔响起。我闭上疲惫的双眼,躺在椅子上小憩。夏天湿热的风掀起一页一页的作文纸,发出动听的声音。我不禁想起了路的开始。是啊,蓦然回首,当年那个毫无梦想的幼稚小孩的身影,在我身上渐渐褪去。
“哈,我又是‘优+’,老师还夸我文笔不错呢!”我举起了我的作文本,得意扬扬地炫耀着。瞧着小伙伴一如既往崇拜的目光,我的小鼻子都要翘到天上去了!从小想象力丰富的我,在作文这方面大显身手。老师的夸奖,让我一次次泡在蜜罐里。嘿!可不是我说,也不是谁都有骄傲的资本吧!
不久,我遇到了钢琴,我猛然间被这个大家伙吸引,就连我视如珍宝的小作文集也被扔在了一边。好景不长,画画又成了我的最爱,蓝天白云小鸟什么都是最好的风景。
妈妈看我一心三用,严令我从中挑出一项用心学习,可我摇摆不定。“切,我可是能三项都学好的人呢!怎么就不让我样样精通呢?”我内心不停地嘀咕着。
可我还是被现实打了脸。
鲜红的“良”如同一枚炸弹彻底把我建立的小小城堡炸为泡影,我紧张地揉搓着手指,等下课铃响我要赶紧回家!
果然,事与愿违。我还是被老师叫去了办公室。我默默地跟在老师后面,看着老师瘦小的背影像一座山屹立眼前,我的心便像揣了头小鹿砰砰直跳。
老师翻着她的小包,拿出了一张纸。我原以为的训斥声并没有到来,便颤巍巍地接过了这张薄薄的纸。“作文竞赛!”我惊呼了出来。老师笑容溢在脸上:“我知道你喜欢写作文,也有这方面的天赋,但我希望你能一直坚持下去,而不是仅仅停留在爱好。你要让它成为你的梦想,如果你愿意,你就来告诉我,好吗?”老师的话语萦绕耳边,在那一瞬间,我看见了老师眼里的星星变得好亮好亮。
我放下了很多东西,开始了真正属于我自己的追梦的旅程,一篇一篇的小作文投在了大大小小的比赛中。读书看报,记一些优美的句子,把自己放在一个自由自在的幻想空间里。时间一点一点过去,不知不觉,我只是玩玩而已的兴趣爱好,就这样变成了我努力追求的梦想。
我走在追梦的路上,这条路花香四溢,五彩缤纷。这条路不仅是追梦的路,更包含着我的快乐与我的辛酸。“嘿,加油!”当初稚嫩的我在路的开始招手,我含笑呼应,前方长路漫漫,我终于能不畏惧艰险,砥砺前行。
我睁开了眼,关上了窗,拿起梦想的笔,书写我漫长的追梦之路。
突然,一只燕子映入我的眼帘,与那无边无际的天空相比,是那么渺小的一个小圆点。我起初并没有在意,可是当它离我越来越近时,我瞥见了它那时而舒展、时而合起的翅膀,便再也移不开眼。它时而在空中滑翔,时而停在高高的树枝上。我想,它是自由的、快乐的、勇敢的。因为它能够在美丽的天空中任意地飞翔,尽情地挥洒欢乐;能够勇敢地挑战自己的极限,展现自己的青春。
一转眼燕子不见了踪影,一阵风姗姗而来,拂乱了我的发丝。我捋了捋前额的刘海,低下头,看见墙角有一株小草在风中摇曳。我想,虽然它只有单调的绿色和矮小的身材,没有花儿那样鲜艳,没有大树般高大,但是它那摇曳的身姿是美的,有着它自己独特的青春与活力。
傍晚,我依旧坐在书桌前,即使外面的世界有狂风暴雨肆虐着,我的心也未曾泛起一丝波澜。打开窗户,我向远处望去,只见一朵小花在田埂上昂首挺立着,似乎在说:“让暴风雨来得更猛烈些吧!”望着它坚强的身姿,我的内心产生深深的敬佩:小草很坚强,有自信和勇气去战胜困难,相信自己的青春与花儿一样璀璨。
青春是什么?我想,青春是一团火,点燃了我们的激情;青春是一面旗帜,召唤我们在人生的道路上勇敢前行;青春是一首悦耳的歌,拨动着我们的心弦;青春是用意志的血滴和拼搏的汗水酿成的琼浆,历久弥香;青春是用永恒的坚强与自信的刚硬筑起的一道铜墙铁壁,固若金汤。
一、单项选择题
1、当篮坛巨星姚明再次因重伤离开离场时,有记者担心他可能永远告别赛场,他却用一贯的姚式幽默回答道:还好,鸡翅依然啃着,生活还在继续。姚明对待生活的态度,启发我们面对挫折应该( )
A、怨天忧人,无所适从B、得过且过,放任自流
C、积极乐观,勇敢面对D、自暴自弃,一蹶不振
2、人要学会走路,也得学会摔跤,而且只有经过摔跤才会学会走路。马克思的这一名言说明的道理是( )
A、经历挫折的人肯定能成功B、挫折是财富,挫折越多越好
C、挫折乃成功之母D、遇到了挫折,要学会自我疏导
3、孪生兄弟庄宏泉和庄汇泉都患有强直性脊柱炎,弟弟丧失行走能力,从小学到大学,哥哥长期背着弟弟艰难求学,手足情深,不离不弃。背学兄弟的事迹告诉我们( )
A、艰苦的环境是取得人生成功的根本保证
B、要善待他人的生命,不用珍爱自己的生命
C、凡事都以个人利益为重,不必考虑他人利益
D、要勇于面对挫折,磨砺坚强意志,做生活的强者
4、下列成语反映坚强意志的正确选项是( )
A、水滴石穿,一曝十寒B、锲而不舍,持之以恒
C、坚持不懈,见异思迁D、虎头蛇尾,功亏一篑
5、4月,四川省都江堰市友爱学校的操场上,汶川地震中双腿高位截肢的学生张春梅正坐在轮椅上和同学们一起上体育课,只见她微笑着推着轮椅娴熟地运着篮球。春梅脸上的笑容告诉我们( )
①要以积极、乐观、自信的生活态度面对挫折②要以坚强的意志与厄运抗争③有了坚强的意志就能克服一切困难④要以积极的情绪应对挫折
A、①②③B、②③④C、①②④D、①③④
6、坚强的意志是我们取得成功的重要保障。下列诗句中能体现磨砺意志的是( )
A、宝剑锋从磨砺出,梅花香自苦寒来B、人生自古谁无死,留取丹心照汗青
C、天生我材必有用,千金散尽还复来D、梅须逊雪三分白,雪却输梅一段香
7、我们每个人都在意志银行里储存了一些意志品质,有些是坚强的,有些是懦弱的。下列属于意志坚强的行为是( )
A、正视自身弱点,勇往直前B、遇到麻烦时,惊慌退缩
C、遇到困难时,消极等待D、学习成绩不好时,唉声叹气
8、俄国教育家乌申斯基说:良好习惯乃是人们在神经系统中存放的道德资本,这个资本不断增值,而人在其整个一生中就享受着它的利息。这句话主要告诉我们( )
A、习惯影响着人的身体健康B、习惯影响着人的思维发展
C、习惯影响着人们的行为D、好习惯使人终身受益
9、小强准备报考理想的学校,可最近一次模拟考试没有发挥出应有的水平。对此,小强的正确认识应该是( )
A、我的理想彻底破灭了B、同学们肯定会嘲笑我
C、我已经尽力了,还是放弃吧D、失败和成功一样对我有价值
10、中国选手李娜在法国网球公赛中赢得女单冠军。她在接受记者采访时说:在失败的时候,我想到过放弃,但还是咬牙挺过来了。这表明( )
①正视挫折,善于调整心态对成功很重要②逆境会使人变得更坚强③坚强的.意志是事业成功的保证④只要意志坚强,事业就能成功
A、①②④B、②③④C、①②③D、①③④
二、简答题
11、22岁的湛江残疾运动员谭业腾,一岁残疾,父母双亡。他意志坚强,面对现实,永不放弃,不断完善自我,超越自我。在广州亚残会赛艇AS男子单人双桨1000米决赛中,不畏强手,以5分00秒877的成功实现了湛江在亚残会上金牌零的突破,充分展现了自强不息、奋勇争先的精神,面对记者他说伦敦残奥会我要冲奖牌!
阅读上述材料,联系七年级所学知识,简要说明我们从谭业腾的事故中得到哪些启示?
12、中国科学院研究院教授、全国自强模范杨佳15岁就考上了大学,19岁教大学,22岁又考入中科院研究生院,24岁成为该院最年轻的讲师然而,29岁那年,一场疾病让她双目失明,在经历了一段失落和沉沦后,她没有向命运低头,克服了常人难以想象的困难,不但完成了美国哈佛大学公共管理硕士课程的学习,更由于出色的才华和表现于1月当选为联合国权利公约专家委员会副主席
阅读材料回答:
(1)杨佳在遭遇挫折后,是如何对待的?
(2)你认为我们应当如何战胜挫折?
三、分析说明题
13、背着妈妈上学的安徽医科大学学生金书家当选为心动安徽年度新闻人物。1991年出生的金书家,母亲自幼残疾,双腿不能走动,2父亲又意外去世,家里生活陷入困境。,上县高中后,他克服重重困难,把母亲带到学校生活,以便照顾。考上大学后,他继续带着母亲,一边学习,一边勤工助学。
(1)请你结合材料,说一说金书家获此殊荣的原因。(答出两方面即可)
There is a big bed
学习目标1. 能听、说、读、写单词“clock”,“plant”,“bike”,“water bottle”和“photo”,并能用句型“There is …”表达某处有某物。
2. 能做“Let’s play”部分的游戏。
3. 培养学生积极与他人合作的优良品质。
4. 教育学生要热爱自己的家。
学习重难点 1. 能听、说、读、写单词“clock”,“plant”,“bike”,“water bottle”和“photo”,并能用句型“There is …”表达某处有某物。
2. 能做“Let’s play”部分的游戏。
教学难点
There be句型的简单运用。
教学过程二次备课
一、课前热身(Warm-up)
1. Free talk
T: Good morning, everyone. How are you today?
Ss: Fine, thank you. And you?
T: I’m fine, too.
2. 教师播放歌曲“What can you do?”的录音,全班学生跟着录音大声唱歌曲,创设学习英语的`氛围。
二、课前预习(Preview)
1. T: You can do so many things. You’re helpful. Look! The room is clean and beautiful. (课件出示一间干净、整齐的房间)
T: What can you see in this picture?
S: I can see a bed, a desk and a …
2. 教师依次指着图片中的bed, window, desk, picture, chair问:“What’s this?”,学生回答:“It’s a / an …”并快速拼读。
T: This is a nice room. I want to make this room nicer. So I need to put more things in this room.
三、新课呈现(Presentation)
1. A. Let’s learn
(1) 教学新单词
T: First, let’s put a clock in the room. (教师边说边点击课件,房间的墙上出现一个钟表) Now there is a clock in the room. Follow me, pleas. Clock, c-l-o-c-k, clock, there is a clock.
教师用同样的方法引出词语:plant, water bottle, bike, photo
(2) 教师用“唱反调”的方式带领学生读几遍新词汇。
(3) 教师介绍张鹏的房间。
T: Do you know what Zhang Peng’s room like? Let’s go and see.
(4) 第一次播放教学录音,全班学生跟着录音读,了解对话的大致内容。
(5) 学生同桌合作,用句型“There is ...”介绍自己班级的物体。
2. A. Let’s play
(1) 教师请三位学生上讲台,表演本部分的“句子接龙”游戏。
(2) 学生三人一组,模仿示例表演“句子接龙”游戏,然后教师请两三组学生上讲台表演。
四、巩固延伸(Consolidation & Extension)
1. 画一画
教师说:“There is a clock, a chair, a bed … in my room.”,学生根据教师的描述画图。
2. 情感教育:Everybody has his own house. The house is a loving bay. The house is a lasting marriage. I love my house.
3. 课堂练习——填入所缺字母,完成单词:
① 瓶子 bot __ __ e ② 时钟 clo __ __ ③ 自行车 b __ __ e
④ 水 w __ t __ r ⑤ 照片 pho __ __ ⑥ 植物 pl __ __ t
4. Check the answer
① tl, ② ck, ③ ik, ④ ae, ⑤ to, ⑥ an
五、课堂小结(Summary)
师生一起总结本节课学习的词汇和句型,学生说说自己还有哪些不懂的地方。
六、布置作业(Homework)
1. 将本节课学习的新单词在四线三格内抄写六遍。
2. 跟着录音朗读本节课所学习的内容。
在本单元中要求学生对在前面五单元中所学过的知识做一次全面的回顾和总结。复习、归纳一般过去时态和现在完成时态,进一步学习动词不定式和宾语从句。能够区别 have been与 have gone的用法;重点学习课文“Under the sea”,明白How important is the sea to our life?
通过利用computer去寻找一些information,进一步熟悉有关如何操作计算机的术语;掌握数词的用法和类似 thousands of短语的用法。通过该单元的学习,要使学生明白海洋对于我们人类的重要,人类与自然应当和谐相处,并尽力保护它的环境。
素质教育目标
1. 在本单元中,首先要让学生在复习的`基础上,建立起正确的包括现在完成时态在内的五个基本时态 (一般现在时、现在进行时、一般过去时、一般将来时、现在完成时) 的时间观念并且能基本做到运用所学过的时态进行交际会话。
2. 要求学生对现在完成时态有一个比较完整的了解,并能与其他时态区别开来。同时,对宾语从句也应当有一个完整的了解,并且能够进行综合运用。
3. 要让学生在合作学习的过程中体到学习的乐趣。
4. 大力运用探究式学习,如进行查找资料、资源共享、话题探讨等,使同学们在学习的过程中获得积累知识和陶冶情操的体验。
5. 本单元的主题与大自然关系紧密,教师应当抓住这个时机对学生进行环境教育,使学生明白人类与大自然应当和谐共处。
Lesson 21
Period: The First Period
Content: Lesson 21
Properties: Tape recorder, Overhead Projector, TV, pictures.
Teaching Objectives: Make the students use the language point in the dialogues.
the usage of the present Perfect Tense
Language Focus:
1. Useful expressions: have an accident; hurt badly;
2. The present Perfect Tense:
What’s happened? They’ve had an accident. Has anyone called the police? Yes, they have. Teaching Procedures:
Ⅰ. Organizing the class
Ask the students to get ready for class.
Greetings between the teacher and the students and a duty report.
Ⅱ. Revision
1. check homework.
2. Revise the present perfect Tense. Ask :
Have you ever been to the Great Wall?
How long have you lived in Beijing?
Get the students to answer the questions.
Make sure they can answer correctly.
Ⅲ. Presentation
1. Show a picture of an accident on TV. Get the students to watch and talk about the accident using some words, such as: have an accident, hurt, badly, fall off, hit …
2. Have the students read and practice the dialogues in pairs.
3. Ask some students to act out the dialogue.
Ⅳ. Puzzle dialogue
Find the best answers by themselves. Check the answer with the whole class.
Ask the students to make up similar questions, then get the other students to answer them.
Ⅴ. Read and act
1. Ask the students to close their books, and then listen to the tape and answer the questions:
Where have Bruce and Sue gone?
Haven’t they ever been to London?
When are they going to be back?
Have the students find the answer to the question. Check the answer with the class.
2. Ask the students to read the dialogue, then practice in pairs.
3. Act out the dialogue.
4. Allow them to change the dialogue to fit a situation they might have at home.
Ⅵ. Exercises in class
Fill in the blanks with the right verb forms.
A: I’m not feeling well. I ________ (get) a cold.
B: ________ you ________ (be) to the hospital yet?
A: Yes, I ________ (go) to see Doctor Li this morning and he ________ (give) me some medicine.
B: ________ you ________ (take) the medicine?
A: Yes, I ________ (take) it just a moment ago.
B: Mr. Li is a good doctor. I think you’ll ________ (be) all right soon.
Answers: have got, Have … been, went, gave, Have … taken, took, be
Ⅶ. Homework
Environment
An effective information system provides users with timely, accurate, and relevant information.This information is stored in computer files.When the files are properly arranged and maintained, users can easily access and retrieve the information they need.传统环境下的数据组织
一个高效的信息系统应向使用者提供及时、准确以及相关的信息。信息存储在系统的文件中。正确地整理和维护文件,可以使用户很容易地检索到他们所需要的信息。
You can appreciate the importance of file management if you have ever written a term paper using 3×5 index cards.No matter how efficient your storage device(a metal box or a rubber band), if you organize the cards randomly your term paper will have little or no organization.如果你在撰写学期论文时曾经使用过3×5索引卡,你会体会到文件管理的重要性。不管你的存储设备(一个金属盒或一个皮筋)效率如何,如果你随意地组织你的卡片,你的学期论文将会缺乏组织性
Given enough time, you could put the cards in order, but your system would be more efficient if you set up your organizational scheme early on.If your scheme is flexible enough and well documented, you can extend it to account for any changes in your viewpoint as you write your paper.如果有足够的时间,你可以将卡片按次序放置,但是如果你早点创建你自己的组织方案,你的系统会做得更有效。如果你的方案足够的灵活并且文档也很齐全,那么在你撰写论文时,可以利用它来说明观点中的任何变化。
The same need for file organization applies to firms.Well-managed, carefully arranged files make it easy to obtain data for business decisions, whereas poorly managed files lead to chaos in information processing high costs, poor performance, and little, if any, flexibility.Despite the use of excellent hardware and software, many organizations have inefficient information systems because of poor file management.公司同样也需要组织文件。组织良好,认真安排的文件可以使商业决策获取数据变得更容易,而组织混乱的文件只能导致信息处理紊乱、成本高、性能差并且灵活性低。尽管使用优秀的硬件和软件,但由于文件组织得不好,很多组织的信息系统的效率还是很低。
File Organization Terms and Concepts A computer system organizes data in hierarchy that starts with bits and bytes and progresses to fields, records, files, and databases.A bit represents the smallest unit of data a computer can handle.文件组织术语及概念
计算机系统按层次组织数据,位、字节、数据项、记录、文件和数据库。位代表计算机中最小的数据单位。
A group of bits, called a byte, represents a single character, which can be a letter, a number, or another symbol.A grouping of characters into a word, a group of words, or a complete number(such as a person’s name or age), is called a field.一组位,叫做一个字节,表示一个独立的字,它可以是一个字母、一个数字或其它的符号。一组字组成一个词、一组词或一个纯数字(例如一个人的名字或年龄)叫做一个字段。
A group of related fields, such as the student’s name, the course taken, the date, and the grade, comprises a record;a group of records of the same type is called a file.For instance, the student records could constitute a course file.一组相关的字段,例如学生的姓名、所选的课程、日期、年级,组成一个记录;一组相同类型的记录被称为文件。例如,学生记录可以构成一个课程文件。
A group of related files makes up a database.The student course file could be grouped with files on student’s personal histories and financial backgrounds to create a student database.一组相关的文件组成一个数据库。学生课程文件可以和学生个人履历文件、个人经济情况文件共同创建一个学生数据库。
A record describes an entity.An entity is a person, place, thing, or event on which we maintain information.An order is a typical entity in a sales order file, which maintains information on a firm’s sales orders.Each characteristic or quality describing a particular entity is called an attribute.一个记录描述了一个实体。一个实体可以是一个人、一个地方、一个东西或一件事情,我们维护与它们有关的信息。销售订单文件提供一个公司销售订单信息,在销售订单文件中,一个订单是一个典型的实体。
For example, order number, order date, order amount, item number, and item quantity would each be an attribute of the entity order.The specific values that these attributes can have can be found in the fields of the record describing the entity order.每个用来描述具体实体的特质或特征的叫做属性。例如,订单号、订货日期、订货量、产品代码和产品数量每一个都是实体订单的一个属性。这些属性的具体取值可以在描述实体订单的记录中的字段里找到。
Every record in a file should contain at least one field that uniquely identifies that record so that the record can be retrieved, update, or sorted.This identifier field is called a key field.An example of a key field is the order number for the order record or an employee number or social security number for a personnel record(containing employee data such as the employees’ name, age, address, job title, and so forth).文件中的每一条记录至少包含一个能被唯一识别的数据字段,这样记录可被检索、更新或分类。这个标识字段叫做关键字段。举个关键字段的例子,如订单号是订单记录的关键字段,员工编号或社会保险号是一个个人记录(包括员工数据,例如员工的名字、年龄、住址、工作职别等等)的关键字段。
Accessing Records from Computer Files
Computer systems store files on secondary storage devices.Records can be arranged in several ways on storage media, and the arrangement determines the manner in which individual records can be accessed or retrieved.从计算机文件中存取记录
计算机系统将文件存储在外存设备中。记录以多种方式存放在存储介质中,而且存放方式决定了单个记录被存取或检索的方式。
One way to organize records is sequentially.In sequential file organization, data records must be retrieved in the same physical sequence in which they are stored.In contrast, direct or random file organization allows users to access records in any sequence they desire, without regard to actual physical order on the storage media.一种组织记录的方式是有序的。在按顺序组织的文件中,数据记录的检索顺序必须与数据的存储顺序相同。相反,不考虑存取介质的物理顺序,直接或随机存取文件允许用户以任何他们想要的顺序存取文件。
Sequential file organization is the only file organization method that can be used on magnetic tape.This file organization method is no longer popular, but some organizations still use it for batch processing applications in which they access and process each record sequentially.顺序文件组织是唯一的一种可以用在磁带上的文件组织方式。这种文件组织方式已不再流行了,但是一些组织仍然使用它来进行批处理,这些处理对每一条记录依次进行存储和处理。
A typical application using sequential files is payroll, in which all employees in a firm must be paid one by one and issued a check.Direct or random file organization is utilized with magnetic disk technology(although records can be stored sequentially on disk if desired).Most computer applications today utilize some method of direct file organization.顺序文件的一个典型应用是工资单,必须依次地对工资单中的所有公司职员支付工资和支票。直接存取或随机存取文件组织方式可用于磁盘技术(但是,如果愿意的话,磁盘中的记录可以按顺序存储)。
Problems with the Traditional File Environment
Most organizations began information processing on a small scale, automating one application at a time.Systems tended to grow independently, and not according to some grand plan.Each functional area tended to develop systems in isolation from other functional areas.Accounting, finance, manufacturing, human resources, and marketing all developed their own systems and data files.传统文件环境存在的问题
大多数组织每次进行的都是小规模的、自动化的信息处理。系统越来越具有独立性,并且不再采用大型的方案。每个功能区的开发都试图孤立于其它模块。会计、金融、生产、人力资源和销售均开发各自的系统和数据文件。
Each application, of course, required its own files and its own computer program to operate.For example, the human resources functional area might have a personnel master file, a payroll file, a medical insurance file, a pension file, a mailing list file, and so forth until tens, perhaps hundreds, of files and programs existed.当然,每个应用都需要自己的文件和计算机系统。例如,人力资源功能区可能需要一个人事主文件、一个工资文件、一个医保文件、一个退休金文件、一个邮件发送清单文件等等,几十个甚至上百个文件或程序。
In the company as a whole, this process led to multiple master files created, maintained, and operated by separate divisions or departments.就整个公司来说,这个过程会导致多种主要文件的创建、维护,并被不同的部门使用。
There are names for this situation: traditional file environment;the flat file organization(because most of the data are organized in flat files);and the data file approach(because the data and business logic are tied to specific files and related programs).By any name, the situation results in growing inefficiency and complexity.对这种情况的叫法有:传统文件环境、平面文件组织(因为大部分的数据组织在平面文件里)、数据文件方式(因为数据和事务逻辑被捆绑于具体的文件和相关的程序中)。无论是哪个名字,这种环境的结果就是低效和复杂性越来越大。
As this process goes on for five or ten years, the organization is saddled with hundreds of programs and applications, with no one who knows what they do, what data they use, and who is using the data.当这种处理方法使用了五或十年,组织已经承载了上百个程序和应用软件,没有人知道这些程序和软件做什么,用什么数据,并且谁在使用数据。
The organization is collecting the same information in far too many files.The resulting problems are data redundancy, program-data dependence, inflexibility, poor data security, and inability to share data among applications.组织可以从多个文件中搜集同一个信息。导致的问题就是数据冗余、程序与数据间相依赖、非灵活性、缺乏数据安全性和应用软件之间无法共享数据。
Data Redundancy and Confusion
Data redundancy is the presence of duplicate data in multiple data files.Data redundancy occurs when different divisions, functional areas, and groups in an organization independently collect the same piece of information.For instance, within the commercial loans division of a bank, the marketing and credit information functions might collect the same customer information.数据冗余和混乱
数据冗余表现为完全一样的数据存放在多个数据文件中。当一个组织中不同的部门、功能和团体独立地搜集相同部分信息时就会发生数据冗余。例如,在一个银行的商业贷款部门里,市场和借贷信息功能可能搜集相同的客户信息。
Because it is collected and maintained in so many different places, the same data item may have different meanings in different parts of the organization.Simple data items such as the fiscal year, employee identification, and product code can take on different meanings as programmers and analysts work in isolation on different applications.由于信息的搜集和维护是在不同的地方进行的,所以相同的数据项会在组织中不同的部分有不同的含义。当不同的应用软件的程序员和分析工作是相互孤立的,简单的数据项,例如会计、员工身份证明和产品编码会表现出不同的意思。
Program-Data Dependence
Program-data dependence is the tight relationship between data stored in files and the specific programs required to update and maintain those files.Every computer program has to describe the location and nature of the data with which it works.程序与数据间相依赖
程序和数据之间的依赖是指存储在文件中的数据和用来更新及维护这些文件的具体的程序间存在紧密的关系。每个计算机程序都必须对它使用的数据的位置和属性进行描述。
In a traditional file environment, any change in data requires a change in all programs that access the data.Changes, for instance, in tax rates or ZIP-code length require changes in programs.Such programming changes may cost millions of dollars to implement in programs that require the revised data.在传统文件环境中,数据的任何更改要求所有存取这一数据的程序发生改变。例如,税率或邮政编码长度的变化要求程序也要随之变动。这种对修改了数据的程序进行设计上的改变可能会花费几百万美元。
Lack of Flexibility
A traditional file system can deliver routine scheduled reports after extensive programming efforts, but it cannot deliver ad hoc reports or respond unanticipated information requirements in a timely fashion..缺乏灵活性
一个传统文件系统在大量的程序设计工作后会提供常规的日程安排报告,但是它不能提供临时的报告或及时回应事先无法预料到的信息需求。
The information required by ad hoc requests is somewhere in the system but too expensive to retrieve.Several programmers would have to work for weeks to put together the required data items in a new file.临时请求所需要的信息存储在系统某处,但由于花费高而无法获取。几个程序员需要花费数周的时间将所需的数据项放到一个新文件中。
Poor Security
Because there is little control or management of data, access to and dissemination of information are virtually out of control.What limits on access exist tend to be the result of habit and tradition, as well as of the sheer difficulty of finding information.缺乏安全性
由于对数据的控制和管理太少,信息的存取和传播实际上是不被控制的。现有的存取限制是由习惯和惯例所造就的,同样也造就了寻找信息的异常艰难。
Lack of Data-Sharing and Availability
The lack of control over access to data in this confused environment does not make it easy for people to obtain information.Because pieces of information in different files and different parts of the organization cannot be related to one another, it is virtually impossible for information to be shared or accessed in a timely manner.缺乏数据共享和有效性
在这种混乱的环境里,对数据的存取缺乏控制使得人们很难获取信息。因为不同文件中的信息和组织的不同部分不能联系起来,所以信息无法及时共享或存取。
The Database Environment Database technology can cut through many of the problems created by traditional file organization.A more rigorous definition of a database is collection of data organized to serve many applications efficiently by centralizing the data and minimizing redundant data.数据库环境
数据库技术可以解决很多有传统文件组织方式引发的问题。对数据库更严密的定义是通过集中数据和减少多余的数据,有效地向应用软件提供组织过的数据集合。
Rather than storing data in separate files for each application, data are stored physically to appear to users as being stored in only one location.数据的物理存放要让用户觉着数据被存放在唯一的一个地方,而不是存储到每个应用程序所需的相互独立的文件上。
A single database services multiple applications.For example, instead of a corporation storing employee data in separate information systems and separate files for personnel, payroll, and benefits, the corporation could create a single common human resources database.一个数据库可以为多个应用程序提供服务。例如,将员工数据存储在相互独立的信息系统和相互独立的员工文件、工资文件和保险金文件中的一个替代做法是,公司可以创建一个通用的人力资源数据库。
Database Management Systems
A database management system(DBMS)is simply the software that permits an organization to centralize data, manage them efficiently, and provide access to the stored data by application programs.数据库管理系统
数据库管理系统(DBMS)就是一个简单的软件,它允许一个组织集成数据、有效管理数据并且通过应用程序提供对存储数据的存取。
The DBMS acts as an interface between application programs and the physical data files.When the application program calls for data item such as gross pay, the DBMS finds this item in the database and presents it to the application program.DBMS在应用程序和物理数据文件间扮演接口的角色。当应用程序需要如工资总额的数据项,DBMS在数据库中查找这一数据项并将它提交给应用程序。
Using traditional data files the programmer would have to define the data and then tell the computer where they were.A DBMS eliminates most of the data definition statements found in traditional programs.A database management system has three components: A data definition language A data manipulation language A data dictionary 使用传统的数据文件,程序员不得不定义数据并且告诉计算机它们在那儿。一个DBMS会去除大部分传统程序中的数据定义声明。
一个数据库管理系统包含三个组成部分: 数据定义语言 数据操作语言 数据字典
The data definition language is the formal language used by programmers to specify the content and structure of the database.The data definition language defines each data element as it appears in the database before that data element is translated into the forms required by application programs.数据定义语言是程序员用来详述数据库内容和结构的形式语言。在数据元素被翻译成应用程序所需要的形式之前,数据定义语言定义了数据库中的每一个数据元素。
Most DBMS have a specialized language called a data manipulation language that is used in conjunction with some conventional third-or fourth-generation programming languages to manipulate the data in the database.This language contains commands that permit end users and programming specialists to extract data from the database to satisfy information requests and develop applications.大部分DBMS有一种叫做数据操作语言的专用语言,它和传统的第三代或第四代程序语言结合起来操作数据库中的数据。这种语言包括允许终端用户和程序设计专家从数据库中提取数据来满足信息需求和应用开发的命令。
The most prominent data manipulation language today is Structured Query Language, or SQL.Complex programming tasks cannot be performed efficiently with typical data manipulation languages.However, most mainframe DBMS are compatible with COBOL, FORTRAN, and other third-generation programming languages, permitting greater processing efficiency and flexibility.现今,最杰出的数据操作语言是结构化查询语言,或者叫SQL。使用典型的数据操作语言,复杂的编程任务无法被高效率地执行。然而大部分中央处理机的DBMS与COBOL, FORTRAN及其他第三代编程语言相兼容,这就使得处理更高效和更灵活。
The third element of a DBMS is a data dictionary.This is an automated or manual file that stores definitions of data elements and data characteristics such as usage, physical representation, ownership(who in the organization is responsible for maintaining the data), authorization, and security.Many data dictionaries can produce lists and reports of data utilization, groupings, program locations, and so on.DBMS的第三个元素是数据字典。这是一个自动或手工的文件,存储了对数据元素和数据属性的定义,例如使用、物理表示、所有权(组织中谁负责维护数据)、授权和安全。很多数据字典可以提供数据使用、分组、程序存储位置等内容的列表和报告。
By creating an inventory of data contained in the database, the data dictionary serves as an important data management tool.For instance, business users could consult the dictionary to find out exactly what pieces of data are maintained for the sales or marketing function or even to determine all the information maintained by the entire enterprise.由于建立了一个数据库中数据的清单,数据字典成为一个重要的数据管理工具。例如,商业用户可以翻阅字典来正确地查找出用于销售或市场功能的数据或者甚至支配整个公司的所有信息。
The dictionary could supply business users with the name, format, and specifications required to access data for reports.Technical staff could use the dictionary to determine what data elements and files must be changed if a program is changed.字典可以为商业用户提供名字、格式和说明,以获取报告所需数据。技术员工可以利用字典来决定如果一个程序发生了改动,那么什么样的数据元素和文件也必须被改变。
Most data dictionaries are entirely passive;they simply report.More advanced types are active;changes in the dictionary can be automatically utilized by related programs.For instance, to change ZIP codes from five to nine digits, one could simply enter the change in the dictionary without having to modify and recompile all application programs using ZIP codes.大部分的字典是完全被动式的;它们只不过是报告。更高类型的字典是主动的;相关程序可自动地使用字典中的变化。例如,将邮政编码由五位改为九位,一个人可以简单地在字典中记录这一改变,不必修改和重新编译所有使用邮政编码的程序。
In an ideal database environment, the data in the database are defined only once and used for all applications whose data reside in the database, thereby eliminating data redundancy and inconsistency.Application programs, which are written using a combination of the data manipulation language of the DBMS and a conventional programming language, request data elements from the database.在一个理想的数据库环境里,数据库中的数据只被定义一次就可以被所有的应用软件使用,因此可以消除数据的冗余和不一致性。结合DBMS的数据操作语言和常规程序语言编写的应用程序需要数据库中的数据元素。
Data elements called for by the application programs are found and delivered by the DBMS.The programmer does not have to specify in detail how or where the data are to be found.应用程序需要的数据元素可由DBMS查找和传递。程序员不必详述查找数据的位置和方式。
Use of a DBMS can reduce program-data dependence along with program development and maintenance costs.Access and availability of information can be increased because users and programmers can perform ad hoc queries of data in the database.The DBMS allows the organization to centrally manage data, utilization, and security.使用DBMS除了减少程序的开发和维护费用,还可以减少程序和数据间的依赖。由于用户和程序员可以对数据库中的数据进行随机查询,信息的可获性和可用性得到提高。DBMS允许组织集中管理数据、应用和安全。
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