初中英语人教新目标 (Go for it) 版七年级上册Unit 9 My favorite subject is science.综合与测试教学设计及反思

这是一份初中英语人教新目标 (Go for it) 版七年级上册Unit 9 My favorite subject is science.综合与测试教学设计及反思，共13页。

主备教师
授课人
课时
授课日期
学生考勤

第1课时
Sectin A 1a-2c
2019年 月 日
班
应到： 人 实到： 人
应到： 人 实到： 人
班
集体备课成员

教学目标
学生能掌握本课重点词汇: favrite, subject, science,P.E., music, math, Chinese, gegraphy, histry,
why,because等
2.学生初步运用有关学科的名词及重点句型“ What's yur/his/her favrite subject? Why d yu/ des
he/she like art?”等谈论所喜欢的学科以及理由。初步理解并试着运用because进行训练。
3.学生能基本听懂含有本课重点词汇和目标语言的听力材料。初步了解听前预测的技巧,并在听的过程中做到有目的地获取有效信息;同时在听的过程中初步感知what/why引导的特殊疑问句。
教学
重难点
重点：通过what/why引导的特殊疑问句来询问喜爱的学科,并通过 because引导的句子给出理由.
难点:what/why引导的特殊疑问句的构成及使用.
教具 准备
录音机、磁带、课本，教学案
教法学法
头脑风暴法、多媒体教学法、小组合作探究法
教学过程
Step 1: Lead-in
A brainstrm with the help f pictures.
1.Ask students t talk abut what kind f sprts they knw
2. Ask students t talk abut what kind f fruit they knw.
3. Ask students t talk abut what kind f clrs they knw
4. Ask students t talk abut what kind f subjects they knw
The teacher can say like this: Yu knw, we have English and Chinese every day. English and Chinese are subjects.S tday we'll talk abut subjects we knw
The ne wh gives the mst answers is the winner
Step 2: Presentatin
1. Play a game: Challenge ur memry.
The teacher shws students sme grups f pictures.students knw all the subjects and can remember them, they can stand up and repeat them
2. Let students talk abut their favrite subject
3. Match the wrds with the pictures in 1a.
Step3: Listen t1b
Befre listening: Read the wrds in la
While listening
1.Play the recrding fr the first time. Students nly listen.
2.Play the recrding fr the secnd time. Students circle the subjects they hear in la.
3. Check the answers.
4.Listen again and read after it.
观察与思考1
1.听力1b中,询问对方喜爱的学科应该问:__________________
回答应该用______________________________
2.听力材料中还有哪一句可以用来表达自己喜欢的学科?
______________________________
Step 4: Pair wrk( Wrk n 1c)
1. Practice the cnversatin in1c in pairs.
2. Rle-play the cnversatin.
Step5: Listen t 2a and 2b
Befre listening
1. Let students lk at the pictures in 2a. And try t get them t guess what is happening.
2. Let students read the sentences in 2a. The teacher gives them help if necessary
3. Let students read the wrds in 2b. The teacher gives them help if necessary
While listening
1. Listen and put the cnversatin in rder.
2. Play the recrding fr the first time. Students nly listen.
3.Check the answers
4.Listen fr the third time and finish 2b
5. Listen and fill in the blanks and ask students t give mre cnversatins.
观察与思考2
1.询问对方喜欢某一学科的理由应该问:__________________
回答应该用__________________
2.思考:
询问对方不喜爱什么学科应该问:____________________________表达自己不喜欢某一学科的理由应该用________________________
学生小组合作讨论,老师归纳总结。
师:询问对方喜爱某一学科的理由应该问: Why d yu
like..?回答应该用: Because it's.
询问对方不喜爱什么学科应该问: What subject d yu nt like?回答应该用:I dn' t like. because it's.
After listening
1. Wrk in pairs. Wrk n 2c
Sample:
A:What’s yur/his/her favrite subject?
B:My/His/Her favrite subject is science.
A:Why d yu like science?/Why des he/she like science?
B:Because it’s interesting.
Step6: Summary
本节课我们初步学习和掌握了“What’s yur favrite subject? Why d yu like ”引导的特殊疑问句谈论别人活自己喜欢的学科，并初步运用because引导的句子和形容词来表达理由。
通过头脑风暴迅速热身,分类复习学过的词汇,因为所涉及的词汇比较简单,因此会扩大学生的参与面，并由此种形式导出新课的目标语言。
通过大屏幕展示图片,让学生一边看图片,边练习单词和句型,加深学生们的印象。学生们通过游戏参与学习,可以增加学习的乐趣,由于游戏设计比较简单,学生的参与度会很高.
通过听的方式输入本课功能句,学习句型,达成知识目标。跟读录音,模仿语音语调,使学生学说最纯正的语言。
引导学生运用合作学习法进行初步的语言实践,引导学生在语境中感知模仿所学语言,培养学生运用语言进行交际的能力
在听力前进行相关活动可以使学生熟悉话题，进行热身，明确任务要求，扫除听力障碍。
设计不同层次的听力任务,引导学生逐步深入的学习,培养良好的听的习惯和技巧。利用观察
思考引导学生注意语法现象,学会归纳简单的语法规则。突破本课教学重难点。同时通过做听力练习,可以帮助学生巩固新学习的单词和句型,并为后面的对话打下语言基础。
板书
设计
Unit9 My favrite subject is science.
（Sectin A 1a-2c）
A:What’s yur favrite subject?
B:My favrite subject
A:Why d yu
B:Because it’
作业批改记录
教学反思
主备教师
授课人
课时
授课日期
学生考勤

第2课时
Sectin A 2d-3c
2019年 月 日
班
应到： 人 实到： 人
应到： 人 实到： 人
班
集体备课成员

教学目标
1.学生能熟练掌握和运用表示星期的词汇: Mnday,Friday, Saturday和短语 fr sure。
2.学生熟练运用“What' s yur//his/ her favrite subject? Why d yu/ des he/ she like art?”句型谈论所喜欢的学科以及理由。
3.学生初步运用“ Wh is yur/his/ her music teacher? When is yur/his/ her gegraphy class?”谈论某个学科老师以及上课时间。
4.学生能够完成相关的口头训练任务,借助what,why,wh,when等特殊疑问句完成有关学科的讨论.
教学
重难点
重点:1.学会一周七天的表达。2.学会运用what,why,when,wh进行提问3.学会根据所给信息完成口笔头练习.
难点:when/wh引导的特殊疑问句的构成和使用。
教具 准备
准备一个标有星期的日历或制作一个能反映一周七天的日历图片；教材；教案
教法学法
归纳法、情景交际法、自主学习与合作学习相结合,练习法。
教学过程
Step 1: Lead-in
1. Check students' hmewrk
2. Chant：
What's yur favrite subject? Science, science, it's science
Why d yu like science? Interesting, interesting, because it s interesting.
What's her favrite subject? Math, math, it's math
Why des she like math? Fun, fun, because it,s fun
Step 2: Presentatin
[Task] Days f the week
1. Display a calendar n the screen and teach seven days f the week.
(1)Let students lk at the calendar. Tell students it's February 1st,.It’s Mnday.
(2)Teach students the ther days f a week.
2. Make them crrect
Lk at the screen, the days are in the wrng rder. Ask students t put these days in the crrect rder.
3. Ask students t talk abut the seven days f a week.They can ask and answer like this:
A: What is yur favrite day? B: My favrite day is Mnday
A: Why d yu like Mnday?B: Because I have music n Mnday. It's my favrite subject.
Step 3: Rle-play
1. Let students lk at the picture in 2d.
Tell students: Frank and Bb are talking abut smething.
2. Let students read 2d silently. Try t find ut the Wh- questins in 2d and circle Wh-questins.
3. Read 2d carefully and answer the fllwing questins:
(1)What is Bb's favrite day?
(2)What are Bb's favrite subject?
(3)Why des bb like histry?
(4)Wh is Bb's P E teacher?
(5)What is Frank,'s favrite day?
(6)Why des Frank like Friday?
4. Play the tape and ask students t read after it twice.Then rle-play the cnversatin.
5. Rle-play the new cnversatins that students make by themselves. The teacher gets sme pairs t play their cnversatin in frnt f the thers. Remind them t pay attentin t their prnunciatin.
Step 4: Grammar Fcus
Read Grammar Fcus twice. Read the sentences after the teacher fr the first time. Read by themselves fr the secnd time
观察与思考2
1.询问喜爱的科目用特殊疑问词_____,询问喜爱某科
目的原因用特殊疑问词______,询问任课教师用特殊疑问词_______,询问某科目的上课时间用特殊疑问词____________.
2.观察 Grammar Fcus中的前三组提问与回答,思考在询问不同人称时,句式有什么变化。
3.观察 Grammar Fcus中的第四组和第五组提问与回答,思考在询问第三人称单数和其他人称时,句式有什么变化。
Step 5: Wrk n 3a
1. Lk at 3a. Ask students t fill the blanks with what,wh r why.
2. Read these dialgues and try t remember them
3. Ask students t act the dialgues ut
Step6 :Wrk n 3b
1. Ask students t read the answers, try t understand the meaning f them.
2. Ask students if they have any difficulties and help them slve them.
3. Ask students t find the key wrds f each answers.
4. Ask students t write cmplete questins.
5. Ask students t write the answers t the questins.
Step 7: Wrk n 3c
1. Grup wrk: Interview sme f the students and finish the chart.
2. Ask students t ask and answer like this:
A: What's yur favrite subject?
B: My favrite subject is music.
A: Why d yu like muic?
B: Because it's fun.
A: Wh is yur music teacher?
B: My music teacher is Ms Xie.
3. Ask students t make a reprt like this:
Li Jingjing's favrite subject is music. She likes it because it's fun. Her music teacher is Ms. Xie. Wang Hua's favrite subject
Step8: Summary
What we have learned tday?
用 chant既能巩固所学知识,又能调动学生学习的积极性,为新课的学习做好铺垫.
通过大屏幕展示图片,让学生一边看图片,一边练习单词和句型,加深学生们的印象。学生们通过对话学习新知识,由于设计比较简单,学生的参与度会很高,而且学习内容贴近生活,学生会很容易掌握重点词汇。
通过默读,培养学生快速寻找信息的能力。
通过仔细阅读,培养学生搜索细节信息的能力。同时,通过
让学生找特殊疑问词和六个Wh疑问句,引导学生感知并初
步学习本课重点.
通过小组表演,引入竞争机制,极大地调动学生的竞争意识。通过对话练习强化学生对Wh疑问句的记忆和掌握.
引导学生对Wh-特殊疑问词和人称以及数的变化进行观察,为接下来3a~3c环节做好铺垫。
通过各种训练形式引导学生加深对Wh疑问句的理解、掌握和运用。同时,通过寻找句中关键词来培养学生搜索细节信息和猜测的能力
由表格中的词汇到对话,再到汇报,注重任
务设置层层递进,由简到难,逐步突破难点。引导学生循序
渐进地掌握重点,最后学以致用,同时,通过此项活动,培养
学生与他人合作的意识,解决问题并报告结果,共同完成学习任务。
板书
设计
Unit9 My favrite subject is science
Sectin A 2d-3c
What's yur favrite subject? Science, science, it's science
Why d yu like science? Interesting, interesting, because it s interesting.
What's her favrite subject? Math, math, it's math
Why des she like math? Fun, fun, because it,s fun
作业批改记录
教学反思
主备教师
授课人
课时
授课日期
学生考勤

第3课时
Sectin B(1a-1d)
2019年 月 日
班
应到： 人 实到： 人
应到： 人 实到： 人
班
集体备课成员

教学目标
1.学生能熟练掌握和运用表示星期的词汇和描述学科特点的形容词及其反义词。
2.学生能够熟练运用what, why, when等特殊疑问句完成有关学科的讨论。同时能够掌握由第一人称向第三人称转换的方法。
3学生能听懂含有本课重点词汇和目标语言的听力材料。掌握听前预测的技巧,并在听的过程中做到有目的地获取有效信息。
教学
重难点
重点:1.表示星期的词汇和描述学科特点的形容词.
2运用what,why,when等特殊疑问句进行有关学科的讨论.
难点:学会制作作息时间表,运用所学知识完成听力任务,学会描述自己喜欢的一天并给出理由
教具 准备
录音机、磁带、课本，教学案
教法学法
情境交际法、小组合作探究法、自主学习与合作学习相结合
教学过程
Step 1: Lead-in
Finish the dialgue with yur partner.
A:What’s yur favrite subject?
B:My favrite subject
A：Why d yu like it?
B:Because it’s...
Step 2: Presentatin
1. Discuss the descriptin wrds students write dwn
2. List the descriptin wrds n the screen. Ask student t remember them as quickly as they can
3. Have a brainstrm .Ask students t list as many descriptin wrds as they can. The ne wh writes the mst wrds is the winner.
4.Finish la. Match the wrds n the left with their ppsites n the right.
5. Teach the seven days f a week.
Step3:Listen t 1b and 1c
Befre listening: Read the wrds in la
While listening
1. Play the recrding fr the first time. Students nly listen.
2. play the recrding fr the secnd time. Students check the wrds they hear in la.
3. Check the answer
4. Lk at lc and teach students hw t see a schedule,Remind students t pay attentin t the activities and the time.
5. Play the recrding fr the third time. Ask students t circle the classes David talks abut.
6. Check the answers.
观察与思考
1.描述学科特点时应该用:学科名称+be+_______
例如:想表达英语很有趣应说:__________________
想表达科学很无聊应说:__________________.
2描述某学科有多个特点时应在形容词中间加连词_______(表并列关系)或连词_______(表转折关系)。
例如:想表达美术很好玩而且空闲应说:_________________
想表达科学很难但很有趣应说:_________________
3.表达某天上什么课应该用什么句式?_________________
After listening
1. Listen again and read after it.
2. Pair wrk: Get students t rle-play the cnversatin.
Step 4: Pair wrk: wrk n ld
1. Wrk in pairs. Talk abut David's favrite subject.Fill in the blanks.
2.Rle-play the cnversatin. Ask sme pairs t act it ut in frnt f the class.
3. Ask students t talk abut their favrite subjects.
Step 5: Grup wrk
1. Design a schedule.
2. Talk abut students' schedule, chse the best ne.
Students can talk like this: We have science, English,Chinese and P. E n Mnday mrning. On Mnday afternn,we have gegraphy and art. On Tuesday, we ,
通过各种训练形式学习描述学科特点的形容词和表示星期的词汇,充分发挥学生的自主学习能力.
通过听的方式输入本课功能句,学习句型,达成知识目标。跟读录音,模仿语音语调,使学生学说最纯正的语言.
使学生能够更加熟练地掌握描述学科特点
句的形容词,并引导学生在语境中感知模仿所学语言。
这是一个巩固性的训练活动,要求学生能运用目标语进行真实的交际。同时,在活动的过程中,学生又练习了人称的转换。学生活动中,教师应四处走动,向学生提使自主学习和合作学习相结合,注重任务设置层层递进,由简到难,逐步突破难点。最后学以致用,把本课学习的重点内容全部融入到任务中,使学生在完成任务的同时全面复习巩固本课重点知识供帮助。
板书
设计
Unit9 My favrite subject is science
Sectin B 1a-1d
Wrds:Mnday,Tuesday,Wednesday,Thursday,Friday,Saturday,Sunday
Descriptin wrds: easy-difficult. free-busy fun-bring cl relaxing
作业批改记录
教学反思
主备教师
授课人
课时
授课日期
学生考勤

第4课时
Sectin B2a-2c
2019年 月 日
班
应到： 人 实到： 人
应到： 人 实到： 人
班
集体备课成员

教学目标
1.学生能根据日程表叙述一天的活动安排或根据文章写出日程表。
2.学生能通过不同的阅读策略,预测文章信息,搜寻主题句、关键句捕捉文章信息,根据上下文理解生词的含义。
3学生能通过一系列的问答,理解文章的逻辑关系和按照时间顺序进行叙事的方法。
4.掌握书信的书写格式。
教学
重难点
重点：1.根据日程表叙述一天的活动安排或根据文章写出日程表。
2.谈论喜爱的学科及其理由,运用形容词对学科进行评价。
3.介绍任课教师和课程时间安排
难点：学习按照时间先后顺序进行叙事的方法。
教具 准备
课本、多媒体课件、学案
教法学法
情景交际法、自主学习与合作学习相结合。
教学过程
Step 1: Lead-in
Ask students t list as many descriptin wrds as they can.
Try t find ut the ppsite f these wrds.
eg: easy-difficult fun-bring
Step 2: Presentatin
1. Use the descriptin wrds t talk abut subjects with ther students.
Eg: I think music is relaxing.
I think music is free and relaxing.
I think math is difficult but interesting
Math is nt easy.
Finish 2a. Write a descriptin fr each subject.Reprt the result. Find ut the favrite subject(s)in class and the subject(s)that students dn't like.
Step 3: Reading
1. Ask students t lk at the picture and guess what Yu Mei is ding.
2.Teach students hw t write a letter in English
3.Ask students t read the first line f the letter quickly, then chse the right answer t the questin.
Questin: What des Yu Mei write abut in the letter?
A. Her favrite fd B. Her hbby(爱好)
C. Her busy day D. Her friend
Skimming: Read 2b quickly and underline the subjects
Yu Mei likes, circle the subjects Yu Mei desn't like.
Scanning: Read 2b, cmplete Yu Meis schedule.
Time
Subject/Activities
Descriptin wrds
8:00-8:50
math
difficult
9:00-9:50
10:00-10:50
11:00-11:50
12:00-1:00
1:00-1:50
2:00-4:00
Detailed reading:
(1) Read the first six lines and fill in the blanks.
① Yu Mei likes________because it’s________but_______.
② Yu Mei als like_______because it's_______and_______.
Yu Meis math teacher says math is_______But she____ _____it because she thinks it's_________and_________.
(2)Read the rest f the letter and answer the questins.
1.What is Yu Mei’s favrite subject? 2. Why des she like Chinese?
3. Wh is her Chinese teacher? 4.What time d her classes finish?
5.Is her art lessn relaxing?
Step 4: Retell
1. Use Yu Mei’s schedule t retell Yu Mei’ s Friday.
Mdel:Yu Mei is very busy n Friday. At 8: 00, she has math
She desn't like it because she thinks it's
Step6: Summary
呈现新知的方式是开放性的,目的是导入阅读的主题,激活学生的背景知识.
引导学生借助图画或文章的中心句预测文细节搜寻主章的大意,这是提高学生阅读技能的一种策略.
通过略读引导学生学会快速搜索关键词的能力。
Scanning也是一种快速阅读策略,通过扫读引导学生学会搜索关键句、理解指代关系的能力。以上两个步骤设计的任务逐层深入,使学生在完成阅读任务的同时感知和掌握知识点
此环节是让学生仔细阅读文章,研究文章的细节信息。通过分层次的问题设计,有助于学生对课文内容的深入理解
板书
设计
Unit9 My favrite subject is science
Sectin B 2a-2c
Yu Mei’s Schedule

Hw t write a letter hw t design a schedule hw t talk abut ne’s day
作业批改记录
教学反思
主备教师
授课人
课时
授课日期
学生考勤

第5课时
Sectin B 3a-SF
2019年 月 日
班
应到： 人 实到： 人
应到： 人 实到： 人
班
集体备课成员

教学目标
1.复习掌握关于星期、学科的词和描述性形容词。引导学生巩固词汇,并运用它们谈论自己对学科和星期的喜好以及原因。
2.复习由特殊疑问词what/when/wh/why引导的核心句型。
3.引导学生掌握电子邮件的书写格式
4.引导学生继续运用所学知识进行阅读的训练。
教学
重难点
●重点:.复习掌握关于星期学科的词和描述性形容词
2.复习由特殊疑问词what/when/wh/why引导的核心句型。
3.继续运用所学知识对书信书写和阅读进行训练。
●难点:掌握电子邮件的书写格式
教具 准备
录音机、磁带、课本，教学案,数字卡片
教法学法
情境创设法、多媒体教学法、小组合作探究法、鼓励评价法、自主学习与合作学习相结合.
教学过程
Step1:Lead-in
Shw students a schedule.
Friday-My busy day
Time
Subject/Activities
Descriptin wrds
AM8:00
Chinese
useful
9:00
histry
interesting
10:00
English
Difficult but fun
11:00
art
relaxing
PM 1:00
science
Fun
2:00
music
free
2. Let students talk abut the schedule.
Eg:I am very busy tday. /I have a busy day tday. At 8:00,
Step 2: Presentatin
1. Ask students hw t write a letter in English. Let students chse which ne is right.
I have a busy day tday. At8: 00, I have math. At 9: 00, I have a busy day tday. At8: 00 ,I have Chinese, it's useful At I have math.At9:00,I have
10: 00, I have science. I like it Chinese, it's useful. At 10: 00 because it' s interesting. Then, / I have science. I like it because it's interesting. Then, we have
Dear Lily,
At8: 00, I have math. At 9: 00, I have a busy day tday. At8: 00,I have Chinese, it's useful At I have math.At9:00, I have 10: 00, I have science. I like it Chinese, it's useful. At 10: 00 because it' s interesting. Then, / I have science. I like it because it's interesting. Then, we have
Yur friend,
Tm
2. Teach students hw t write an e-mail message.
3. Tell students: Yu want t invite yur friend Lily t g shpping. And yu are ging t meet her at ten n Sunday at the schl gate.
Step 3: Read 3a
Skimming: Number the parts f an e-mail message[1-3].
2. Scanning: Read 3a, answer the questins.
(1)Why is he writing an e-mail t Mei Ling?
( 2)Is Dale busy n Friday afternn?
(3)When will they meet?
(4)What subject desn't Dale like?
(5) Can Dale meet Mei Ling n Saturday?
3. Detailed reading:
(1)Read 3a and try t find descriptin wrds in it
(2)Read 3a again, and cmplete Dale's schedule.
Dale’s Friday afternn
Time
Subjects /Activities
Descriptin wrds
观察与思考
1.阅读65页第6部分内容,结合53页2b和54页3a,总结一下英文书信和电子邮件的书写格式.
称谓:_________________
正文:_________________
落款:_________________
2.总结一下本课介词的使用:
(1)早晨、下午、晚上用介词_____,但具体到某一天的早晨、下午、晚上用介词_____.
(2)表示在星期几用介词_______.
(3)固定搭配:① Thank yu_______
② Is that OK____yu?
3.总结一下本课动词的固定搭配.
(1) Thank yu fr__________(2)want________
(3)Let's______
Step 4: Retell and write
1. Use Dale's schedule t retell Dale's message.
2. Finish 3b. Fill in the schedule belw fr students asses n Friday.
3. Ask students hw t write dwn the activities f a day.
写作指导
(1)除了按照时间顺序进行描写外,还用到了一些时间连词,如:then, after that, after lunch。这样,使文章的联系更加紧密,更有层次感。
(2)描述某学科特点时可用多个形容词,并在中间加连词and(表并列关系)或连词but(表转折关系)如:
(1) I think music is relaxing.
(2) I think music is free and relaxing.
(3) I think math is difficult but interesting
(3)应注意变换句式,不要总是采用一种句式结构。如:
① I am very busy tday.还可以表达成 I have a busy day tday
② It is fun.还可以表达成 It's a fun class
③ My favrite subject is art.还可以表达成 I like art best.
4. Ask students t use the schedule in 3b t write dwn the activities f their Friday.
Eg: I have a happy day tday. At 8: 00, we have English .I think it's useful and interesting. Then at 8: 55, we
Step 5: Self Check
1. Review the imprtant pints f this unit
(1)表示星期的词汇
weekdays Mnday,
week
weekend
(2)描述学科特点的形容词
easy--difficult
Descriptin wrds
Finish Self Check.
Check the answers.
围绕“一天的活动”这个话题,通过表格的形式把本单元重点语言知识进行了总结和归纳。便于学生对本课重点形成清晰的知识体系。同时,又检查核对了前一节
课的作业.
英文书信和 e-mail相似,通过对书信格式的讨论,引出email,既复习了英文书信,又学习了email的格式。
Skimming是一种快速阅读策略,通过略读引导学生学会快速搜索关键词的能力.
此环节是让学生仔细阅读文章,研究文章的细节信息。通过分层次的问题设计,更有助于学生对课文内容的深入理解。
通过写作指导为下面的写作做好准备。引导学生不仅要学习课本基础知识,而且也要关注文章结构和写作手法,同时也要学以致用.
围绕本单元主题,通过mind-map和表格的形式把本单元重点语言知识进行了总结和归纳。便于学生
对本课重点形成清晰的知识体系.
板书
设计
Unit9 My favrite subject is science
Sectin B 3a-SF
Dear Lily,
At8: 00, I have math. At 9: 00, I have a busy day tday. At8: 00,I have Chinese, it's useful At I have math.At9:00, I have 10: 00, I have science. I like it Chinese, it's useful. At 10: 00 because it' s interesting. Then, / I have science. I like it because it's interesting. Then, we have
Yur friend,
Tm
作业批改记录
教学反思