




已阅读5页,还剩17页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
Unit 2 Lets play sports!Comic strip and Welcome to the unit教学目标1掌握常见的几种体育运动的名称。2使用适当的语言谈论体育运动。教学内容四会内容词汇:walking really bowl time tennis volleyball词组:go swimming句型Do you often play football? I often play football after sch001 What about you?三会内容句型Really? 1walktomybowlmanytimes a day教学准备1漫画中Hobo拿着足球的图片。2各种体育运动的图片。3录音机或光盘。4课件。教学步骤说明在本课时,我们采取先上Welcome to the unit,再上Comic strip的设计。_一方面,这样更便于以旧引新,导入单元话题:另一方面,也为教师在教学设计时提供新的思路,旨在引导教师根据需要灵活设计各板块的教学。Welcome to the unitStep I呈现l通过回顾上一单元的内容,导入本单元话题sports。教师说:Do you remember Mille,Sandy, Simon and Daniel? Who likes sports?启发学生回忆课文回答: Simon is good at sports再问:What about Amy? What sport is Amy good at?启发学生回忆课文回答:She is good at swimming2教授,volleyball和tennis。 方法一:出示sandy和Millie打排球的图片。教师说Look at Sandy and Millie What sport are they good at? They are good at playing volleyball They can play volleyball very well.板书volleyball,接着出示Kitty打网球的图片。教师说: Look at Kitty. She likes tennis very much板书:tennis。 方法二:呈现排球或网球的实物。教师说:Look at the balls in my hand What is this big one? Its a volleyballWhat about this small one? Its a tennis ball板书: volleyball和tennis。3与学生存真实语境下进行交流,加强对新知识的巩固教师说:Can you play volleyball? Do you like volleyball? Are you good at playing tennis? Do you enjoy playing tennis? 鼓励学生根据自己实际情况同答。Step II操练1指导学生完成课本A部分的练习。教师说:Sports are very interesting Students like sports very much Please look at the pictures in Part A Do you Know what sports they like?指导学生看图并补全句子。2与学生在真实语境下进行交流。教师说: .,do you like playing volleyballfootballtennis7? .,are you good at playing volleyballfootballtennis? .,do you loveenjoy swimmingplaying volleyballfootball tennis? What sports do you likeenjoylove? What sports are you good at?3鼓励学生根据实际情况,用自己学过的知识彼此进行交流。教师说:Do you like sports? Lets know what sports your friends like。组织学生同桌问答或四人小组问答。StepIII呈现1向学生呈现go swimming。教师说:Its very hot today .Do you think so? Whats your favourite sport in summer?鼓助学堆根据情境思考并回答:My favourite sport is swimming接着对学生说:Thats a good idea I like swimming too Lets go swimming this weekend.板书:go swimming。2向学生介绍B部分的情境,并让他们听录音回答问题。教师说Amy and Simon like sports very much Now, they are talking about sports Listen to the tape and tell me when Amy goes swimming(Every week)3指导学生跟录音鲫溃对话。教师可以分配男生和女生分角色朗读,并提醒学生注意模仿语音语调,如需要,可互换角色再读一遍。Step IV操练1安排学生在四人小组内根据实际情况练习对话。教师说Do you know what your friends favourite sport is? Please work in groups of four2学生在对话过程中教师巡视,并根据学生需要提供帮助:play badminton(打羽毛球)play basketball(打排球),play table tennis(打乒乓球)等Step V展示1选不同层次的几组学生上台表演,并在表演结束后给予鼓励和表扬2为学生提供各种情境,让学生模拟在不同语境下交流各种体育运动 情境一:老师和学生。 情景二:利用体育明星的照片,假设记者现场采访。Comic stripStep I呈现1创设语境,向学生呈现新知识。教师说:Sports are good for us gut sometimes. We are very busy and have no time I think walking is also good板书walking。教师还可以用动作帮助学生理解。教师接着对学生说I like walking and 1 walk in the park many times a week板书time。为了帮助学生理解,教师还可进一步说明If you have timeyou can walk many times a dayYou can walk in the morningYou can walk after lunch or after supper I think walking many times is good for you教师接着问学生:.,do you like walking? Do you often walk to school? Do you often go waling in the park?鼓励学生根据实际情况回答。在与学生交流的过程中,教师可以用“Oh,really?”进行反馈,让学生在有语境的情况下,体会这一表达的含义和用法,板书really。2出示课本中Hobo手拿足球的图片,呈现漫画背景。教师说:Look,whats in Hobos hand? He has a football in his hand I think he likes football very much .Do you think so? But what about Eddie? What is his favourite sport?鼓励学生发表自己的观点,I司时复现他们已知的有关运动的知识。3指导学生带着问题听录音并理解相关内容。教师晓Now, lets listen to Eddie and Hobos dialogue and answer the question:What sport does Eddie like?为学生播放前两幅漫画的录音,让学生回答问题。4让学生带着悬念听余F的录音部分。教师|兑Does Eddie really like walking?学生听完后两幅漫画的录音后回答问题,并在教师的鼓励下给出结论:Eddie walks to his bowl many times a dayStep II操练1指导学生跟录音集体朗读。教师蜕:Please listen to the tape and following in chorus. Pay attention to the pronunciation and intonation.2将全班分成两大组进行分角色朗读。教师说:These two teams read Eddies part And these two read Hobos part,please启发学生有感情地朗读,从音色、节奏、速度等方面进行设计。Step III展示1组织学生同桌分角色有感情地朗读对话,并设计符合漫画内容的面部表情和肢体语言。教师说:Work in pairs and read the dialogue between Eddie and Hobo You can add your own ideas2让学生看漫画进行配音活动。教师说Lets dub this comic. .,can you demonstrate with me to the whole class?之后再选不问层次的学生进行展示。3对有能力的学生,鼓励他们根据所给的语境,发挥自己的想像,自由会话。StepIV家庭作业1熟读本课时所学内容,记忆词汇、词组、句型。2有能力的学生熟背Comic strip和B部分内容。3完成教师布置的书面练习。4预习Reading。Reading教学目标1认识一名叫Li Hua的足球运动员。2用英语介绍自己喜欢的一名运动员教学内容四会内容词汇:player member club free enjoy hope dream true词组:free time come true句型:He is a new member of Huanghe Football Club He looks strong and plays football very well. I hope his dream comes true.教学准备1有关足球的图片(运动员、世界杯等)2其他体育明星的图片。3 卡纸。4录音机或光盘。5课件。背景知识 本单元主要学习各种体育运动,并介绍自己喜欢的运动项目及各自的运动习惯等。在这一课时中,学生将通过Simon的介绍,认识一位足球运动员李华,了解他的个人信息及足球运动的知识。 世界杯(FIFA World Cup)是由国际足球联合会统一领导和组织的世界性的足球比赛,每四年举行一次。它是世界上规模最大、影响最大、水平最高的国家队足球比赛。在世界杯比赛中,夺冠次数最多的足球队是巴西国家队,共夺得五次世界杯冠军。教学步骤Reading 1Step I呈现1与学生就“体育运动”进行交流,复习上节课内容。教师说Id like to test your memory What sport do Sandy and Millie often play?What sport does Kitty like?What about Simon?What about Amy?鼓励学生回忆所学内容并回答:Sandy and Millie often play volleyball Kitty likes tennis Simon likes football。Amy is good at swimming接着教师与学牛就各自的真实的信息进行交流。教师说:What is your favourite sport? How do you play it?2出示一张贝克汉姆的图片,向学生呈现新知识。教师说:Who is this man?鼓励学生回答This is David Beckham教师接着说:What sport is he good at? He is good at football He is a football starWho likes David Beckham in our class? Oh,he is favourite football player板书:player。教师进一步介绍贝克汉姆He is from EnglandHe comes from England,but now lives in the USA板书come from。He is a member of Los Angeles Galaxy Football Club It is a football club in the USA板书member和club。教师继续与学生交流Do you like David Beckham? Do you want to be a football player like him? Do you want to play football as well as David Beckham? Would you like to have dinner with him? Would you like to take photos with him?教师可以提供各种学生会感兴趣的情境,鼓励学生回答。对回答Yes的学生说:Really? I hope your dream comes true 。板书:hope,dream,true和come true,在必要时,可进行适当翻译,帮助学生明确含义。Step II操练1让学生就各自喜欢的体育明星与同桌进行交流,鼓励他们在真实语境下使用新知识。教师可以先与一位学生做示范。Sample conversationS1:,what sport do you like?S2:I like .S1:Who is your favourite player?S2:My favourite player isS1:What club is heshe m?s2:HeShe is a member ofS1:Where does heshe come from?S2:HeShe comes fromSI:Do you want to have dinner with himher?S2:.S1:Oh l hope your dream comes true2在学生充分交流后,选几组学生进行展示。Step III呈现1导入本课文章,指导学生快速阅读。教师说Today, lets meet another football playerWhat is his name? Please read the article on page 20 quickly and tell me 让学生快速阅族找到答案:His name is Li Hua2指导学生闽滇文章,了解每小节的大意。教师说:1 want to know more about Li HuaHere are my questions教师向学生呈现B1部分中的四个问题,接着说In which paragraph can I find the answers? Please help me write the correct paragraph numbers in the blanks in Part B13根据任务要求学生听录音并仔细阅读,进一步掌握细节信息。教师一边向学生呈现B3部分中的卡片,一边说Millie wants to make a card about Li Hua .Can you listen to the tape? Then complete the information on itAge:_Club:_Looks:_Come from:_ 对有能力的学生,不仅要求他们填写卡片,还可要求他们用完整地句手表达出来:His name is Li HuaHe is 22 years old. He is a member of Huanghe Football ClubHe looks strong He comes from Guangdong He lives in BeijingStep IV操练1指导学生完成B2部分中的笔头练习。教师说:Millie has some questions about Li Hua She needs your help Please read after the tape and find the answers教师将B2部分的问题呈现给学生,指导他们跟录音朗读文章,然后完成B2的对话。在学生填写的过程中,教师可以巡视并随时加以指导和纠正。2鼓励学生同桌之间扮演Millie和Simon进行对话,加深对课文信息的掌握。教师说:Its the role-play time Work in pairs and talk about Li Hua like Millie and Simon You can ask more questions教师可以先与学生进行对话示范,井鼓励学生根据课文内容提出更多自己的问题,以巩固他们对Li Hua的认识。如: (1)Where does he live?(He lives in Beijing.) (2)What does he do every day?(He plays football every day) (3)What does he do in his free time? (He studies English and enjoys listening to music)(4)Why does he listen to music?(Because it makes him happy)(5)Whats Li Huas dream?(He wants toplay in the next World Cup)3选不同层次的几组学生表演对话,并给予鼓励和表扬。Step V活动1为学生提供事先准备好的体育明星的图片,让他们选出自己最喜欢的运动员。 教帅说:Here are many famous sports stars Do you know them? Who is your favourite player?而后,指导学生模仿B3部分制作一张卡片,介绍自己最喜欢的这名运动员(姓名、年龄、所属惧乐部,外貌、家乡、居住地等)。教师可以事先做好一张卡片,介绍教师自己最喜的运动员,给学生以启发和示范。教师说 My favoufite player is., Look,this is a card about himher. Will you please make a card about your favourite player?You can use the one in Part B3 as a model You can also give more information有能力的学生可以在卡片上增加更多的信息。当学生对某些信息不了解时,教师要鼓励学生用英语互问互答当学生之间无法解决时,教师可给予帮助。教师说:Do you have any trouble? If so,please put up your hand and ask your classmates in English Id like to help you too2学生完成卡片后,教师请不同层次的多名学生上台,手拿运动员的图片和卡片,用英语向大家介绍My favourite sports star在本课时中只要求学生能简单介绍即可。3由于课堂时间有限,很多学生没有机会展示自己的作品。教师可以将所有学生的作品都收集来,张贴在教室的墙上,进行展示。Step VI家庭作业1熟读课文。2有能力的学生熟背。3完成教师布置的书面练习Reading 2Step I呈现1为学生提供一个表格,让他们回忆课文并填写表格。教师说:Do you remember Ii Hua? Who is he? Can you complete the table about Li Hua? 表格如下:Li HuaAge JobClubHobby Dream Come from2通过与学生就表格信息进行讨论引出本课时需讲解的语言点并板书player,member,club,free(free time) enjoy(doing),dream,hope,true(come true),come from等。3通过创设情境、与学生真实交流和例句展示等方式,帮助学生掌握上述语言点的用法。以free,free time,enjoy为例,教师说:I like listening to music I enjoy beautiful music. When I am freeI often listen to music What do you often do when you are free?What do you enjoy doing in your free time?在与学生的交流中,帮助学生体会并发现这些语言点的含义及用法。4鼓励学生对不懂的内容提问,针对学生的提问,教师解答并帮助他们扫清障碍。 如:look strong,makehappy等。教师可以说:Who enjoys reading books in our class?Who enjoys listening to music?Who enioys sports?Books make us clever. .looks very cleverMusic makes us relaxed Sports can make us happy and strongSo looks strongStep lI操练Mini-dictionaryClub (1ine 4) n. group of people who meet together regularly, for a particular activity,sport,etc(俱乐部) Do you want to join this club?come from (1ine 4 ) to have as your place of birth or the place where you live (来自) This teacher comes from the USAdream (line 12) n. a wish to have or be sth especially one that seems difficult to achieve(梦想) My brothers dream is to be a writerenjoy(1ine 9)v. to get pleasure from sth (享受.的乐趣) Bob enjoys swimming in summer.Free (1ine 8) adjwithout particular plans or arrangements;not busy(空闲的) Are you free next weekend?hope (1ine 11)v. to want sth to happen and think that it is possible(希望) l hope you11 have a good timemember (1ine 3) n. a person or a thing that belongs to a particular group (成员) He is a member of the school Tennis ClubPlayer (page 20) na person who takes part in a game or sport(运动员)I want to be a basketball playerTrue (1ine 12)adjconnected with facts rather than things that have been invented or guessed(真实的) This is a true storycometrue (linel2) to become reality(变为现实) Can my dream come true?1引导学生完成B4。教师说:Now,we know Li Hua very well. Can you help Millie complete the sentences in Part B47?2为学生提供更多的练列,巩固所学的知识。(1)Daniel enjoys (read)books about sports.(reading)(2)Jim is a _(成员)of our school voileyball team.(member)(3)Mike hopes his dream_(成真)(comes ture)(4)This tennis_(play)_(play)very well(player;plays)(5)My favourite basketball star is from the USA(改为同义句) My favourite basketball star_the USA(comes from)Step lll展示1利用上一节课学生制作的体育明星卡片,鼓励学生从中任选一人进行介绍,写成文章,但不出现姓名。然后,让学生上台介绍,让其他学生猜所介绍的运动员是谁。教师说:Look at the cards on the wall. Please choose a player and write an article about himher Dont tell us hisher name Then you can come to the front and introduce himher. We will try to guess who heshe is2选择不同层次的学生参加展示活动,帮助他们用完整的语言介绍一位运动员。Step IV家庭作业1熟读课文,争取复述或背诵。2记忆词汇、词组、句型。3完成教师布置的书面练习。4预习Grammar。Grammar教学目标1理解行为动词一般现在时的用法。2掌握行为动词一般现在时的肯定句,否定句、疑问句及其肯定和否定回答的基本用法。3结合本单元话题,用一般现在时进行交际。教学内容四会内容 词汇:drawing weekend shop 词组:aton weekends=aton the weekend of course 句型lYouWeThey like sports HeSheIt likes sports IYouWeThey do notdont like sports HeSheIt does notdoesnt like sports Do Iyouwethey like sports? Yes,youlwethey do No,youIwethey dont Does hesheit like sports? Yes,hesheit does No,hesheit doesnt教学准备1各种活动的图片。2写有各种活动(体育活动和日常话动)短语的纸条3配有辅助练习的课件或投影:教学步骤Step I呈现1利用图片导入行为动词的一般现在时。教师呈现NBA篮球明星的图片井对学生说:Look,who are these men in the picture?引导学生回答:They are basketball players They play basketball very well将这两句话写在黑板上,用彩色笔将动词圈出。教师继续说This is Kobe He is very tall He looks very strong将这几句也写在黑板上、用彩色笔将动词圈出。2让学生比较黑板上的句子,启发学生发现不同之处。教师说Look at these sentences Pay attention to the verbs We use the verb“to be” in these three sentences while we use the verb“to do“ in these ones .3利用投影或课件为学生提供一些例句,指导他们找出行为动词,并在语境的帮助下体会行为动词的一般现在时的用法。教师说:Kobe plays basketball very well Many students like him They often watch his games on TVIn my free time,I like watching TV too But my likes reading HeShe often reads storybooks将上述内容呈现给学生并解释:当谈论经常性、习惯性的动作,爱好,能力等时,常用行为动词的一般现在时。4指导学生认真阅读上述内容,提醒学生注意其中行为动词的形武 当主语是第一、第二人称和第三人称复数时,行为动词使用其原型。当主语是第三人称单数时,行为动词使用其第三人称单数形式。教师说:When the subject is shesheit,we need to add ans to the verb5教师带领学生一起学习第三人称单数动词变化表。教师说Do you want to know how to add an ”s” to the verb? Lets read the table on page 23 together. How many ways are there to add an“s”? What are they? 对学生易错的变化方式,要重点强调,如:以辅音字母+y结尾的动词,去掉y,再加ies等。Step II操练1在投影或黑板上呈现一些动词,让学生写出它们的第三人称单数形式put_(puts) enjoy_(enioys) write_(writes)fly_(flies) play_(plays) have_(has)guess_(guesses) match_(matches) go_(goes)2向学生介绍A部分的情境,指导学生完成课本上的练习。教师说Millie is writing about herself and her classmatesPlease help her complete the sentences in Part A with the words in the box请五个学生将各自写好的句子朗读出来,其他学生核对答案:Now,who can read the sentences to us?Others listen carefully and check the answersStep III展示1让学生用五句话介绍自己、家人或朋友的习惯、爱好和能力。教师说:I want to know more about you,your family and your friends Please write five sentences to introduce yourtheir habitshobbies and abilities2学生准备过程中,教师适时给予帮助和指导,尤其提醒学生注意动词第三人称单数形式的使用。3教师选择不同层次的学生上台介绍自己、家人或朋友的习惯、爱好和能力。在学生介绍的过程中,教师应与学生加强互动,实现真正的交流。Step IV呈现1为学生创设情境,呈现行为动词一般现在时的否定句、疑问句及回答。教师说:Millie and Simon are talking about their favourite sports Please read their conversationMillie:I like ONeil very much He plays basketball very wellSimon:Of course. He looks very tall and strong. Do you often watch his games?Millie:Yes,I do. What about you?Simon:Oh,I dont like basketball. My father and I like football very much Mlille: What about your mother?Simola:My mother doesnt like football at a11She likes tennis Mlille:Well,does she like Federer,a famdus tennis player?Simon: No,she doesntShe likes Nadal because he is handsome2教师带领学生一起学习课本上的表格。教师说:Do you want to know how to make negative sentences and ask and answer questions using the verb“to do”in the simple present tense?Lets read the tables together对学生易错的变化方式,要重点强调,如句中有了助动侧do或does,行为动词用原形等。Step V操练1向学生介绍B部分的情境,指导学生完成课本上的练习。教师说:Look at this table It tells us the activities Millie and her classmates like Please complete the questions in Part B and then Dse the information in the table to answer them2指导学生利用表格信息,以同桌为单位进行问答,鼓励学生提出更多的问题。 教师说Would you please work in pairs to ask and answer questions according to the information in the table?You can ask more questions如: (1)Does Daniel like walking? Yes, he does. (2)Do Amy and Sandy enjoy reading? Yes,they do. (3)Does Daniel like drawing? No,he doesnt. (4) Do Millie and Kitty enjoy swimming? No,they dontStepV活动1将事先准备好的写有各种活动(体育活动和日常活动)短语的纸条放在一个盒子里。让学生从盒子里随意抽取一张纸条,其他学生根据纸条内容向该生提问,谈生根据实际情况回答。教师说Lets play a game. I have many flashcards in this boxThey are all about some spots and daily activities please take one card out and show it to us.而后,教师示范向该生提问:,do you play computer games every day?该生回答完后,教师再问班级其他学生Does play computer games every day?2教师选择不同层次的学生参与活动,确信他们能够熟练表达。StepVII呈现1教师向学生呈现C部分中的新知识。教师说:1 want to buy some books forI want to shop也is Satutday or SundayDo you often shop at weekends?板书shop 和at weekends。教师可以利用日历、购物袋、图片等呈现。2教师与学生进行简单的对话What do you often do at weekends?Who often shop in our class?检验学生对新知识的掌握情况。StepVIII操练1向学生介绍C部分的情境,指导学生完成课本上的练习。教师说:Daniel and Simon are talking about their weekends Complete their conversation with the correct forms of the verbs in brackets2学生填写完成后,指导他们进行同桌对话。3教师选择几组学生进行展示,确信他们能够熟练表达。Step IX展示1给学生布置任务,让他们在小组中就weekend activities编写对话。教师说:We know a lot about the weekend activities of the Class 1,Grade 7 students Now please work in groups of four and talk about your own weekend activities After that,write down the conversation in your notebooks2给学生五分钟的准备时间,然后教师选择能力不同的学生上台表演,适时加以鼓励和表扬。StepX家庭作业1复习语法部分的内容。2完成教师布置的书面练习3预习Integrated skills。Integrated skills教学目标1从听力材料中获取信息。2用所得信息将语篇补充完整3就相关话题进行交流。教学内容四会内容词汇:table tennis else lot词组a lot of= lots of句型:What else do you like to do? It makes me feel great Reading is fun教学准备1人物图片。2录音机或光盘。教学步骤A What sport do you like?Step I呈现1教师与学生就“What sport do you like?”进行口头交流。一方面复习原有知识,另一方面导入A部分的主题。教师说:What sport do I like? Can you guess?You can ask me some questions and tryto get the answer鼓励学生向教师提问。2呈现Millie,Simon,Kitty,Amy,Sandy和Daniel的图片,教师通过与学生的对话帮助学生回顾前面所学的知识并教授新知识。教师说:Do you remember these students? Do you know what activities they like?鼓励学生根据已知的信息回答Sandy likes playing volleyball Simon likes playing football Amy likes swimmingStep II听力训练1教师呈现A1部分的情境并指导学生根据自己原有的知识,完成A1的部分信息 教师说Mr Wu is asking his students about their favourite sports. Can you help
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 工厂安全培训知识点
- 2025重庆巫溪县事业单位考核招聘98人备考考试题库附答案解析
- 2025四川泸州交通物流集团有限公司及下属公司招聘10人备考考试题库附答案解析
- 法务专业团队咨询方案
- 2025湖北省省直机关遴选公务员214人备考考试题库附答案解析
- 哲学博士路途
- 工厂安全培训文案课件
- 2025西安经开第九小学实习教师招聘备考考试题库附答案解析
- 2025贵州安顺市中医院引进专业技术人才备考练习试题及答案解析
- 枣庄市台儿庄区2025届公费医学毕业生定岗备考考试题库附答案解析
- 2024版2025秋贵州黔教版综合实践活动五年级上册全册教案教学设计
- 转作风重实干课件
- 村干部饮水安全培训总结课件
- 安全生产治本攻坚三年行动半年工作总结
- 单招备考科学方案
- 医美咨询培训课件
- 海船船员适任 评估规范(2024)轮机专业
- DB50-T 1463.2-2023 牛羊布鲁氏菌病防控技术规范 第2部分:人员防护
- NoSQL数据库应用与实践 课件 第1-6章 认识NoSQL - 增删改查
- 20世纪宋史研究:主要趋势、热点领域与未来展望
- 2025年度餐饮店知识产权保护与合伙人合同
评论
0/150
提交评论