第一篇：視頻格式大小比較

視頻格式大小比較？mp4 avi 3gp rmvb wmv mkv mpg vob mov flv按大小排序？

? 樓上說的很正確, 還有一種比較方法, 就是同一個內(nèi)容用這些格式來壓縮, 然后比較大小, 在網(wǎng)絡(luò)上常見的大小數(shù)序如下, 小到大

flv, 3gp, mp4, mov, mpg, wmv, rmvb, mkv, avi

解釋一下, flv都是那些視頻網(wǎng)站在用, 為了網(wǎng)絡(luò)傳輸, 肯定用最小的大小

3gp是手機在用, 這個也肯定不會太大

mp4都是移動設(shè)備在用, ipod和一些手機和播放器, 大了裝不下的mov是蘋果電腦常用格式, 蘋果向來以效率著稱

mpg其實很大的, 之所以大家都覺得它小, 是因為它是早期格式, 那時候的電影清晰的不高, 所以mpg的大小也不大

wmv是微軟的, 用這個格式壓縮的人不多, 很多都是惡意添加許可證, 讓你必須連接到某個網(wǎng)站

rmvb是最常見的格式, 當初是為網(wǎng)絡(luò)傳播設(shè)計的, 要求很小的大小就能有很高的清晰度, 雖然比不過上面那些, 不過性價比很高, 用的人很多

mkv是新興的格式, 大小不太了解, 只是電驢上面那些人經(jīng)常用這個格式壓縮高清影片, 每個都1G多, 很少見到小的

avi通常是發(fā)布最原始的無壓縮的電影時用的格式, 大小就是DVD的4.2G, 提供給別人壓縮并添加字幕的 drganfly-二級 2009-11-11 02:24

? 1.首先要明確 LZ列明的都是封裝格式 不是編碼格式 他們各自都可以封裝特定的數(shù)種編碼格式 只有編碼格式?jīng)Q定文件的大小 封裝格式只是將數(shù)據(jù)打包起來而已

例如: mp4 avi mkv flv mov都可以封裝h264 嚴格來說就不存在可比性了

2.不過 這些封裝格式大多數(shù)情況下封裝的編碼格式有普遍的特定性 按照同等畫質(zhì)的前提下 各自所需要的數(shù)據(jù)量 可以粗略的排列他們的大小

mpg > 3gp > vob > rmvb > mov > flv > avi = wmv > mp4 = mkv

再次提醒 這是在要達到同等畫質(zhì)的條件下的文件大小的比較！

3.按照網(wǎng)絡(luò)上流傳的格式 其常見的文件大小來排列的話:

vob > mkv = avi > rmvb > mov = mp4 > flv = 3gp 匿名 2009-11-11 10:05

第二篇：比較大小 教案

比較大小

一、教學目標

1、掌握100以內(nèi)數(shù)的順序，會比較100以內(nèi)數(shù)的大小。

2、引導學生獨立思考，初步學習對數(shù)量的估計，逐步建立數(shù)感，理解多一些、多得多、少一些、少得多的相對性，并能夠用準確地語言進行表述。

3、培養(yǎng)學生的合作與交流的意識與能力。

4、激發(fā)學生的學習興趣，發(fā)展思維能力。

二、教學重難點：

理解多一些、多得多、少一些、少得多的相對性，并能夠用準確地語言進行表述。

三、教學重難點：

正確熟練地進行比較

四、教具準備；

例4放大圖兩幅、投影片。

五、教學過程：

（一）、復習。

1、讀出下列各數(shù)。35 76 89 90 96 100

2、老師報數(shù)，學生在本子上寫數(shù)。六十九 九十三 八十 三十 一百

3、口答。(1)一個兩位數(shù)，高位上是5，低位上是9，這個數(shù)寫作()。(2)一個數(shù)，百位上是l，十位、個位都是0，這個數(shù)寫作()。

（二）、新授。

1、教學例5。

(1)出示小棒圖。教師問：左邊有多少根小棒?右邊有多少根小棒? 根據(jù)學生回答，教師板書； 42 37 教師追問：“左右兩邊的小棒，哪邊的多?(左邊多)42和37兩個數(shù)比較。哪個數(shù)大?”

學生回答，老師再做說明，42和37相比較，42大，37小，我們用“>”來表示它們的關(guān)系。(2)出示計數(shù)器圖。(3)讓學生觀察后問：

“左邊的計數(shù)器表示多少?右邊的計數(shù)器表示多少?”學生回答后，老師板書：23 25．又問：“23和25這兩個數(shù)相比較，哪個數(shù)大，哪個數(shù)小，應(yīng)該怎樣表示?”老師在○里填上“<”大家齊讀式子兩遍。另一幅圖提問個別學生誰大于誰?把你的想法說給大家聽一聽。

3、做課本第42頁“做一做”。

先讓學生獨立做題，教師巡視指導，對有困難學生可對照數(shù)目表，做完后集體訂正。

4、投影出示例6．

教師：紅球有幾個?(58個)藍球有幾個?(15個)黃球有幾個?(10個)大家一起從15數(shù)到58，數(shù)的過程體會到15到58要經(jīng)過好多的數(shù)。

教師告訴學生，58比15多得多，象剛才的題目我們就可以說，紅球比藍球多得多。請一個同學從10數(shù)到15，從中感受到l0到15比較接近，我們就可以說15比10多一些，象剛才的題目，我們就可以說黃球比藍球少一些

5、第43頁“做一做”

根據(jù)題意每人用“多一些、少一些、多得多、少得多”說一句話。

（三）課堂小結(jié)

大家說說今天有什么收獲？

六、教學板書

生活中哪些地方用到了“多一些、多得多、少一些、少得多”這樣的詞語？

第三篇：大小作文

2011

1、小作文：

Directions: Some international students are coming to your university.Write them an email in the name of the Students' Union to

1)extend your welcome and

2)provide some suggestions for their campus life here.You should write about 100 words on ANSWER SHEET2.Do not sign your own name at the end of the letter, Use “Li Ming” instead.Do not write the address.(10 points).Dear Friends, On behalf of the Students’ Union of Beijing Foreign Studies University, I would like to extend our heartfelt welcome to all of the overseas students from all over the world to study in our university.It is my great pleasure to propose several practical suggestions to you.In the first place, life in this prestigious university perhaps is not as satisfactory as what you expected.You may be tightly bound by continual classes, excessive homework and exams.In the second place, in spite of all these adversities, you will still enjoy your life in this esteemed institution.All types of extracurricular activities such as sports meets, speech contests, different social gatherings and dancing parties provide ample opportunities to make friends.All in all, although there are many things lacking, life in our campus is a worthwhile period in your whole lifetime.Wish you enjoy your life here!Yours sincerely, Li Ming 親愛的朋友們：

謹代表北京外國語大學學生會，向來我校學習的世界各地的海外學生表達衷心的歡迎。

我很榮幸地向你們提出一些實用的建議。首先，這所著名學府的生活也許不像你們所期待的那么令人滿意。你們可能會陷入無盡的課程、大量的作業(yè)和考試。其次，盡管有這些課業(yè)，你們?nèi)詫⑾硎苓@所大學的生活。運動會、演講比賽、聯(lián)誼會和舞會等各種各樣的課外活動提供大量交朋友的機會。

總之，盡管有很多不足，我們的校園生活仍將是你一生中一段美好的歲月。希望你享受這里的生活！

您真誠的，李明

2、大作文：

Directions: Write an essay of 160-200 words based on the following drawing.In your essay, you should 1)describe the drawing briefly.2)explain its intended meaning, and 3)give you comments.You should write neatly on ANSWER SHEET2.(20 points)參考范文

As is symbolically illustrated in the cartoon, two individuals respond to the same event in completely diverse ways.The person on the left airs his dissatisfaction and disappointment when a bottle is overturned, while the man on the right is hurry to raise it up, with a sweet smile on his face.We are informed that various folks take different attitudes toward the same scene.The aim of the portrayal is to illustrate that keeping optimistic is of utmost significance to both our society and our life.In the first place, as an extremely vital psychological quality, optimism brings us creative power to play, arouses our enthusiasm for work and helps us overcome difficulties.In other words, with pessimism, achievements can hardly be made.In the second place, keeping optimistic gives us light when we are in dark and encouragement when we are dismayed.It is optimism, rather than genius and extraordinary ability, that inspires us to cope with any arduous task.With optimism, the goal we intend can be reached, and so can the hard nut be cracked.In conclusion, keeping optimistic encourages people to learn wisdom, humanity and self-confidence, and is a crucial and unavoidable aspect of any individual’s development of character and competence.參考譯文：

如圖所示，兩個人對同一件事情的反應(yīng)截然相反。當瓶子倒下時，左邊的人表達了不滿和失望，然而右邊的人卻面帶微笑，急著把它扶起來。我們得知不同的人對同一事物看法不同。

這幅漫畫的目的是闡明保持樂觀對于我們的社會和生活都至關(guān)重要。首先，作為一種極為重要的心理素質(zhì)，樂觀給我們的娛樂帶來了創(chuàng)造力，點燃了我們對于工作的熱情，幫助我們克服困難。換而言之，如果悲觀，我們很難取得任何成績。其次，在我們身處黑暗時，樂觀帶來光明；在我們沮喪灰心時，樂觀賦予勇氣。正是樂觀，而非天才或卓越的才能，激勵我們應(yīng)對任何艱難險阻。擁有樂觀，我們才能實現(xiàn)計劃中的目標，并且克服困難。

總之，保持樂觀可以鼓勵人們?nèi)W會獲得智慧、博愛和自信，因此是個人性格和能力的培養(yǎng)過程中不可缺少的重要組成部分。2011 Part A: 小作文

Directions:

Write a letter to a friend of yours to

1)recommend one of your favorite movies and

2)give reasons for your recommendation.You should write about 100 words on ANSWER SHEET 2.Do not sign your own name at the end of the letter.Use”Li Ming”instead.Do not write the address.(10 points)Dear Bob, As one of your closest friend, I'm writing the letter in purpose of recommending one of my favorite movies to you, Around the World in Eighty Days.The primary factors for my recommendation as as follows.For one thing, this is a movie of science fiction which tells us an exciting story about an English gentleman,Mr.Phileas Fogg, who makes a bet with his clubmates and managers to travel around the world in eighty days.For another, it gives us a vivid description of the many difficulties and incidents which happen on his journey.Wish you enjoy the movie.Looking forward to your reply.(104 words)Yours sincerely, Li Ming

參考譯文

鮑勃：

作為你最好的一位朋友，我寫這封信是為了向你推薦我最喜歡的電影之一：《八十天環(huán)游地球》。

我推薦的主要原因如下。首先，這是一部科幻電影，講述了一位英國紳士的一個激動人心的故事。菲力·弗格先生跟他的俱樂部伙伴打了個賭，并設(shè)法在八十天之內(nèi)環(huán)游了地球。其次，電影生動描述了他在旅途中遇到的困難和發(fā)生的故事。

希望你喜歡這部電影。期待著你的回信。

你真誠的，李明

Part B: 大作文 Direction: Write an essay of 160-200 words based on the following drawing.In your essay ,you should 1)describe the drawing briefly, 2)explain its intended measing, and 3)give your comments.You should write neatly on ANSWER SHEET 2.(20 points)As is subtly portrayed in the cartoon, two tourists are taking sightseeing on a small boat while discarding their picnicing leftovers casually into a lake.Unfortuantely, the lake is already littered and teamed with flowing rubbish like plastic containers, fish-bones, banana skin, watermelon rind, bottles, tins, food wrappings, and so on.And below the drawing, there is a topic which says: “after” the travel or “me” in the travel.From the portrayal, we can conclude that the painter wants to convey such a message: a good many popular places are flooded with visitors, who spoil the beauty of nature by creating and leaving behind God-knows-how-much trash.On the one hand, tourism, as a multibillion-dollar business, is booming everywhere.Some people, laboring under the belief that tourism serves as an engine of economic growth, seem to ignore its negative effects on the environment.Nevertheless, it is my view that these are not concerns that we can shrug off lightly.On the other hand, tourism has exerted great pressure on the environment we are living in: water is polluted, the ecological system is disturbed, and natural resources have been excessively used.Undoubtedly, tourism could not be banned in any country as it does help to shore up the economy in places which offer few sources of income.The significant point is that the unchecked growth of the travel business may render the development of an economy unsustainable.It is high time that we enhanced people's awareness to rectify this by taking the environmental protection into consideration.(255 words)參考譯文

如圖所示，兩名游客正在一艘小船上觀光，同時把野餐的剩余垃圾隨意丟入湖中。不幸的是，湖中已經(jīng)堆滿了漂浮的塑料盒、魚骨、香蕉皮、西瓜皮、瓶子、罐頭、食品包裝等各色垃圾。在圖畫下方，有個小標題寫明：“旅程之‘余’”。從漫畫中，我們可以得出結(jié)論：畫家想要表達下述信息：成群的游客涌入很多景點，通過生產(chǎn)并丟棄大量的垃圾從而破壞了大自然的美觀。一方面，旅游業(yè)作為一項數(shù)十億美元的產(chǎn)業(yè)，正在世界各地迅猛發(fā)展。有些人認為旅游業(yè)是經(jīng)濟發(fā)展的引擎，似乎忽視了其對環(huán)境的負面影響。然而，我認為我們必須充分關(guān)注這一問題。另一方面，旅游業(yè)已經(jīng)對我們生存的環(huán)境造成了巨大的壓力。水受到污染，生態(tài)平衡遭到破壞，自然資源被過度開發(fā)。

毫無疑問，由于在其他收入很少的地區(qū)，旅游業(yè)確實有助于發(fā)展經(jīng)濟，因此任何國家都無法禁止旅游業(yè)。重要的是旅游業(yè)毫無節(jié)制的發(fā)展可能使得經(jīng)濟發(fā)展不可持續(xù)。通過考慮環(huán)境保護因素，我們早就該提高人們的意識來扭轉(zhuǎn)這個現(xiàn)象了。

2010 Part B Directions:

Write an essay of 160-200 words based on the following drawing.In your essay, you should

1)describe the drawing briefly，2)explain its intended meaning, and then

3)give your comments.You should write neatly on ANSHWER SHEET 2.(20 points)文化“火鍋”：既美味又營養(yǎng)

文字說明：佛、解構(gòu)、人本、功夫、畢昇、儒、禮、后現(xiàn)代、老舍、莎士比亞、愛因斯坦、道、仁、天鵝湖、啟蒙、京劇等

As is symbolically illustrated in the portrayal, there is a boiling hotpot containing various ingredients of multi-cultures.These pluralistic cultures can be categorized as celebrities home and abroad as Bi Sheng, Lao She, Shakespeare and Einstein, philosophical concepts as Buddhism, Taoism, Confucianism, benevolence, rite, humanism, enlightenment, post-modernism and deconstruction, as well as performing arts as Peking Opera, Kong fu and Swan Lake.We are informed that the culture “hotpot” is both delicious and nutritious.The purpose of the cartoonist is to show us that instead of being outdated and of little value in a rapidly modernizing world, cultural blending should be encouraged and maintained.On the one hand, mosaic cultures are part of the universal heritage of humanity and they are powerful means of bringing together diverse peoples and social groups.Consequently, cultural reintegration has become indispensable as a means of promoting further culture development and maintenance.On the other hand, for China, as for any other rapidly developing country, there is a danger that age-old customs and traditions may become lost in the shadows of modernization.If kung-fu, Peking Opera or swan lake ballet ever perished from the earth, it would be a tragedy of immeasurable proportions.In my view, multi-cultures can be kept alive by the people with the time to do so, and is extremely vital in ensuring a community’s future development and prosperity.As a consequence of successful commercialization efforts, unwavering government support and growing interest overseas, the future of cultural blending looks brighter and more secure than ever before.如圖象征性所示，一只沸騰的火鍋中擁有諸多多元文化元素。這些多元文化可分為畢昇、老舍、莎士比亞、愛因斯坦等國內(nèi)外名人，佛、道、儒、仁、禮、啟蒙、人本、后現(xiàn)代、解構(gòu)等哲學概念，以及京劇、功夫、天鵝湖等表演藝術(shù)。文字說明顯示：“文化‘火鍋’，既美味又營養(yǎng)?！?/p>

畫家的目的是告訴我們文化融合并未過時或失去價值，相反還應(yīng)鼓勵和保持。一方面，多元文化作為全體人類遺產(chǎn)的一部分，是將不同人群和社會群體融合的有力方式。因此，文化融合作為促進文化發(fā)展和保護的一種方式，已經(jīng)不可或缺。另一方面，中國跟世界上其他快速發(fā)展的國家一樣，年久的習俗和傳統(tǒng)面臨著消失在現(xiàn)代化陰影里的危險。如果京劇、功夫或天鵝湖從地球上消失，那將是不可估量的悲劇。

在我看來，如果人們能為多元文化花費時間的話，那么它就能得以保護。這對確保社會將來的繁榮和發(fā)展都至關(guān)重要。由于成功的商業(yè)努力、政府堅定不移的支持和不斷增長的海外興趣，多元文化的將來會比過去任何時候更明朗、更安全。Part A Directions:

You are supposed to write for the postgraduate association a notice to recruit volunteers for an international conference on globalization.The notice should include the basic qualification for applicants and the other information which you think is relevant.You should write about 100 words on ANSWER SHEET 2.Do not sign your own name at the end of the notice.Use “ postgraduate association ” instead.(10 points)

Volunteers Needed

January 9, 2010 To improve students’ability and enrich extracurricular activities, the Postgraduate’Association is recruiting volunteers for an international conference on globalization to be held on April 7, 2010 in Beijing.To begin with, applicants should have Chinese nationality, a strong professional spirit, cheerful personality and be aged under 35.In addition, candidates must have outstanding skills at English listening comprehension and the ability to speak Chinese and English fluently.Finally, students with relevant professional experience are preferred.Those postgraduates who are interested in taking part in it may sign up with the monitor of their classes before February 1, 2010.Everybody is welcome to join in it.Postgraduate Association 參考譯文

招募志愿者

2010年1月9日

為提高同學們的能力并豐富課外活動，研究生會現(xiàn)招募2010年4月7日在北京舉辦的一次國際全球化會議的志愿者。首先，應(yīng)聘者必須具有中國國籍、較強的職業(yè)精神、令人愉快的個性，年齡在35歲以下。其次，申請人需具有卓越的英文聽力水平以及流利的中英文演講能力。最后，具有相關(guān)職業(yè)經(jīng)驗的學生優(yōu)先考慮。有興趣參加的研究生請于2月1日之前在本班班長處報名。歡迎大家積極參加。

研究生會 2008 Part B: Directions: Write an essay of 160-200 words based on the following drawing.In your essay, you should 1)describe the drawing briefly, 2)explain its intended meaning, and then 3)give your comments.You should write neatly on Answer Sheet 2.（圖略）

文字說明：“你一條腿，我一條腿；你我一起，走南闖北?！?/p>

As is symbolically illustrated in the cartoon, supporting each other with their powerful hands, two handicapped adolescents are continuing their new journey on the ground.Crutches left behind, they have successfully cracked the hard nut of lameness which might have confused the majority of the disabled.The caption indicates, “You have merely one leg and so do I.Helping each other, we can travel all around.”

Undoubtedly, we can deduce from the portrayal that the cartoonist is trying to attract our attention to the issue of cooperation.According to a survey conducted among a group of people who were in the same college class 10 years ago, those who are ready to give their cooperation to others all become rich or managers of all field, while not a single young man having difficulty in getting along with their classmates becomes an executive or boss.Why those who are excellent in team work tend to be managers or own their own enterprise in their later life? The answer seems self-evident.On the one hand, if you are competent in profession, but have difficulty in getting along with your colleagues and even your boss, you can hardly survive the corporation.On the other hand, your chances of success are much higher with wide circle of friends who are willing to cooperate with you to provide information and resources.It is my view that, first of all, we can frequently use the drawings to enlighten the juvenile to learn to cooperate successfully with each other.On the other hand, whatever difficulty or situation we are confronted with, those who have the spirit of cooperation and team work are nearer to success.Just as John Adams, the second U.S.president quoted from the ancient Greek Aesop’s Fables, “United we stand, divided we fall.”

2009 Directions: Write an essay of 160-200 words based on the following drawing.In your essay, you should 1)describe the drawing briefly, 2)explain its intended meaning, and then 3)give your comments.You should write neatly on Answer Sheet 2.As is symbolically illustrated in the portrayal, the Internet is a spider web of thousands of networks, linking schools, universities, businesses, government agencies, libraries and millions of individuals.Undoubtedly, the Internet exerts such a profound effect on our life that it revolutionizes the way of people’s living and thinking.The exaggerative and impressive cartoon has subtly revealed the duality of the relationship between man and Internet.On the one hand, something like information superhighways, the Internet can bring many conveniences into the school, home and office.With a basic computer and modem, any individual can call up information about almost anything from almost anywhere and anytime.But on the other hand, a great many people admit that they are too much addicted to Internet to maintain a regular and wholesome lifestyle.Such a waste of time inevitably leads to their failure in their life and work.Hence, it is necessary for us to use Internet in a reasonable way and restrain from overindulgence.For one thing, in addition to providing us many of the facilities and services we now must travel to obtain, with the Internet, the computer will even let us communicate directly with other homes and with information sources worldwide.For another, as nearly all activities could be conducted in the comfort of our homes, we could all become hermit-like, never feeling any need to leave the computer.Accordingly, the challenge of the Internet means we should consider how we can use it, so that it won’t control us.Part A: Directions: Restrictions on the use of plastic bags have not been so successful in some regions.“White Pollution”is still going on.Write a letter to the editor(s)of your newspaper to 1)give your opinions briefly, and 2)make two or three suggestions.You should write about 100 words.Do not sign your own name at the end of the letter.Use “Li Ming”instead.You do not need to write the address.Dear Editors, I have been reading your newspaper for many years with a great enthusiasm and interest.It is my view that limiting the use of disposable plastic bags is of utmost significance.To crack this hard nut, I would like to propose several practical recommendations as follows.First and foremost, it is imperative for us to ban the free use of disposable plastic bags.In addition, we should develop possible alternative forms to replace them, such as paper or clothing bags.Last but not least, plastic bags should be offered in a much higher price in department stores or supermarkets.I hope you will find the above proposals conducive and I would like to discuss this matter to further details.Your prompt attention to my suggestions would be highly appreciated.Yours sincerely, Li Ming

第四篇：《比較大小》教案

100以內(nèi)數(shù)的大小比較

望珺乙

教學內(nèi)容

人教版小學數(shù)學教材一年級下冊第42頁。教學目標

1．知識與技能：使學生學會比較100以內(nèi)數(shù)的大小，并體會比較兩數(shù)大小的方法。

2．過程與方法：培養(yǎng)學生觀察、比較、提出問題和解決問題的能力。3．情感、態(tài)度與價值觀：利用現(xiàn)實有趣的情境激發(fā)學生的求知欲、學習數(shù)學的興趣。

重點難點

重點：掌握比較100以內(nèi)數(shù)的大小的方法。難點：正確比較100以內(nèi)數(shù)的大小。教具學具 教具準備：課件。學具準備：數(shù)字卡片。教學設(shè)計

一、創(chuàng)設(shè)情境，導入新課

1．談話：小朋友們，森林王國這幾天可熱鬧了，大家都爭先恐后地要報名參加數(shù)學夏令營活動，想加入嗎？

可名額有限，人數(shù)又太多，怎么辦？于是，聰明的小猴提出：只要你能回答我的三道問題，闖過三關(guān)，就有機會去夏令營，誰愿意做勇敢的闖關(guān)者？

2.出示：

第一關(guān)：42里面有()個十和()個一。

從右邊起，第一位是()位，第二位是()位，第三位是()位。9是()位數(shù)，100是()位數(shù)，23是()位數(shù)。指名學生回答。

第二關(guān)：填上適當?shù)姆枺ǎ净颍迹﹐ 10○7 15○18

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集體用手勢表示后指名兩人說說，你是怎樣比較的。第三關(guān)：請數(shù)出37后面的5個數(shù)。同桌相互數(shù)數(shù)。

3．談話：祝賀小朋友們，你們闖關(guān)成功了，現(xiàn)在就可以順利參加夏令營了。

二、自主探索，靈活比較

1．出示課件（小松鼠和小兔正在海邊拾貝殼，小松鼠拾了37個，小兔拾了42個）。

(1)談話：瞧，小松鼠和小兔正在海邊拾貝殼呢，你還看到了什么？ 看著這幅圖你想知道什么？小松鼠和小兔比，誰拾得多呢？ 你會比較嗎？(2)合作交流。

談話：請把你的想法先說給小組同學聽一聽（小組內(nèi)交流）?？赡芮闆r：

a．我用數(shù)數(shù)的方法，42在37的后面，所以42比37多。b．四十幾個比三十幾個多，所以42比37多。

c．42的十位上是4，37的十位上3，4大于3，所以42比37多。誰愿意把你的想法說給大家聽一聽（在班內(nèi)充分交流）。(3)談話。

在這道題里比較哪一個小動物拾的貝殼多就是比較37與42哪一個數(shù)大。你能用一個數(shù)學符號表示它們之間的大小關(guān)系嗎？

教師板書：42 37 指定學生板演：＞

全班學生讀一讀算式：42＞37。(4)提問。

誰能起來再和大家說說你是怎樣比較它們的大小。（多指名學生充分說一說）2．出示課件。

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(1)談話：參加夏令營的小伙伴人人都想取得好成績，想比比自己的能力，于是他們請來了珠算先生當裁判，出難題考考大家。你能寫出計數(shù)器上表示的數(shù)并比較它們的大小嗎？

學生自己填寫。

交流時要求學生說出比較的方法。(2)指名學生板演：23<＼25 0 追問：這時候，你又是怎么比較的？ 多指名學生充分說說自己的比較的方法。(3)完成“做一做”的第1題。

談話：再來挑戰(zhàn)一次，比一比這次誰的能力更強。集體交流，說說你的比較方法是什么。

三、實際應(yīng)用，形成內(nèi)需 談話：比一比誰的反應(yīng)最快。

1．搶答游戲：填上“＞”或“＜”（“做一做”的第2題）。請你用相應(yīng)的手勢快速表示。交流，說說自己的比較方法。2．寫數(shù)游戲。

(1)下面我們再來動動小手，寫出三個個位上都是6的兩位數(shù)。學生寫好后教師提問：你寫了哪三個數(shù)？誰最大？誰最?。?你能把這三個數(shù)按一定的順序排列嗎？（這個學生在黑板上排，其余學生在座位上排）為什么這樣排？（可以從小到大，也可以從大到小排）個位上是6的兩位數(shù)有幾個？（順次說一說）

(2)寫出三個十位上都是6的兩位數(shù)，比一比哪個最大，哪個最小。讓學生都獨立完成后再相互交流。

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四、課堂總結(jié)

提問：通過參加這次數(shù)學夏令營活動，你學到了什么數(shù)學知識？（揭示板書課題：100以內(nèi)數(shù)的大小）

學會了什么本領(lǐng)，能和小朋友說說你的體會嗎？（學生說說自己的體會）板書設(shè)計

教學反思

100以內(nèi)數(shù)的大小比較這節(jié)課，是在學習100以內(nèi)數(shù)的認識和順序以及20以內(nèi)數(shù)的大小比較的基礎(chǔ)上學習的。100以內(nèi)數(shù)的大小比較是小學階段整數(shù)大小比較的基礎(chǔ)和重點?，F(xiàn)對本節(jié)課，反思如下：

一、創(chuàng)設(shè)情境，讓學生體會數(shù)學的趣味性和實用性

本節(jié)課對教材進行了合理的開發(fā)與整合，構(gòu)建了幾個大活動板塊，添加了一些活動素材，如創(chuàng)設(shè)故事情節(jié)——“拾貝殼比賽”，使學習素材富有現(xiàn)實意義，更具趣味性和挑戰(zhàn)性，不僅充分調(diào)動了學生學習的主動性和積極性，也豐富并促進了他們學習情趣的養(yǎng)成。

二、在學習知識的同時注意思想方法的滲透

本節(jié)課注重為學生創(chuàng)設(shè)一些開放的問題情境，如“你是怎樣比較42與37的大小的？”，“你是怎樣想的？”等，而且注重為學生提供開放的探索空間，讓學生能充分地進行獨立思考、探討交流等，在這種開放的學習過程中，使學生能積極去探尋解決問題的策略，主動去交流自己解決問題時的思維過程，充分去感受比較策略的多樣化，增強了學生的自主意識，逐步加深學生對數(shù)學學習的認識和理解。

三、尊重學生，兼顧學習活動的有效性和發(fā)展性

本節(jié)課充分尊重學生的生活經(jīng)驗，充分尊重學生的選擇，使他們在借助計數(shù)器比較的過程中經(jīng)歷了數(shù)學化的過程，有效地進行了比較方法的優(yōu)化；充分尊重學生的理解，使他們在學習活動中不斷感受到比較的現(xiàn)實意義和價值，而且充分尊重學生，也使得學生在有效的學習活動中，知識體驗和情感體驗不斷得以豐富和提升，真正促進了他們的持續(xù)發(fā)展。

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第五篇：識字《大小》

識字《大小》教學設(shè)計

廣安市特殊教育學校

彭曉燕

教學目標：

1、2、學生能初步比較兩個物品的大小，理解大小的含義。學生能認讀生字“大、小”。

3、能在生活中認讀大小，提高學生的生活識字能力。

4、培養(yǎng)學生觀察能力，激發(fā)學生識字的興趣。A生：（程科銘、左青龍、李鳳林）能初步比較兩個物品的大小

能認讀生字“大小”，理解大小的含義。能在生活中認讀大小，培養(yǎng)學生的識字能力。培養(yǎng)學生的觀察能力，激發(fā)識字的興趣。B生：（周尚慧、辛大潤、鄧雨）能初步比較兩個物品的大小。

能看圖認讀生字“大小”，在老師設(shè)定的環(huán)境中理解大小的含義。能激發(fā)學生的識字興趣，提高學生的識字能力。C生：（曾朝誠、周欣、康欣雨、向雨涵）能參與課堂活動 能跟讀生字“大小”。

能在老師設(shè)定的環(huán)境中，理解大小的含義。教學重點：

能認讀生字“大、小”，理解大小的含義。教學難點：

1、能認讀生字“大、小”，理解大小的含義。

2、能在生活中認讀大小，提高學生的生活識字能力。

教學準備:ppt、實物大小不用的兩個蘋果、生字卡、圖片（大門、小門、大床、小床、大碗、小碗）教學過程

一、創(chuàng)設(shè)情境，激發(fā)興趣

1、師：同學們看看今天哪個卡通人物來到了我們的課堂？ 生：熊大熊二

2、解決問題

師：熊大熊二遇到了一個難題，你們愿意幫助他們嗎？（生：愿意）這里有兩個蘋果，熊大想吃大蘋果？你能幫他找到這兩個蘋果中哪個是大蘋果嗎？熊二想吃小蘋果，誰來幫幫他？找到哪個是小蘋果？

注：PPT同時出示（大蘋果）（小蘋果）

3、熊大熊二想和同學們一起來學習認識“大小”，以后他們就可以自己解決這樣的難題了。出示課題：識字《大小》

二、探究新知

1、認讀生字“大小”

師：剛才同學們知道了，這是大蘋果，那你們知道這個字怎么讀嗎？教師拿出大的生字卡讓學生認讀 教師范讀，教生讀（讓學生舉起自己字卡中的大字）,開小火車讀

師：同學們和熊大熊二一起學習了大這個生字，知道了大蘋果的大，小蘋果的小呢？他又長什么樣子呢？ 師：拿出“小”字卡，和學生一齊認讀

教師范讀，教生讀（讓學生舉起自己手中字卡中的小字），開小火車讀

2、通過看圖比較認讀

熊大熊二為了感謝同學們幫他們找到自己想要的蘋果，還和小朋友們一起高興的學習了認識大小兩個字。他們想請小朋友們到他家去做客，你們想去嗎？好那我們現(xiàn)在就出發(fā)。

來到熊大熊二的家，你們看到了什么？師：出示圖片，請學生觀察兩扇門有什么不一樣？

門（大門、小門），一齊看圖說一說抽B、C生來指認圖片，A生將自己手中對應(yīng)的大小字卡貼在大門和小門的旁邊。走進門，我們看到兩張床，一齊看圖說一說哪張是大床，哪張是小床？抽B、C生來指認圖片，A生將自己手中對應(yīng)的大小字卡貼在大床和小床旁邊。

我們再看看廚房有什么？兩個碗，哪個是大碗，哪個是小碗？抽B、C生來指認圖片，A生將自己手中對應(yīng)的大小字卡貼在大碗和小碗旁邊。

三、拓展練習，回歸生活

1、在生活中，找到我們今天學過的“大小”。

好了，小朋友們剛才參觀了熊大熊二的家，現(xiàn)在熊大熊二帶我們到他家附近去看看，你們還能找到“大、小”兩個字嗎？如果你們能找到一會熊大熊二會拿好吃的款待大家。

師：PPT出示圖片，抽生來找到各種標牌，與實物上的大小兩個字，帶領(lǐng)其他同學讀一讀。

3、小朋友，用你們的火眼金金再去找找我們生活中還有哪些地方能見到大小兩個字，把他告訴自己的爸爸媽媽。

四、總結(jié)

1、今天熊大熊二歡迎你們到他家來做客，給同學們帶來了美味的食物，你們想吃嗎？那你能找到這個食物上有我們今天學過的小字嗎？師：分發(fā)食物，逐個指導學生找到法式小面包中的”小”字。

五、板書設(shè)計

識字《大小》