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四年級下冊《小英雄雨來》教案
1. 通過在教師指導下的獨立閱讀，初步理解內(nèi)容，學習小英雄雨來熱愛祖國、憎恨敵人、機智勇敢的優(yōu)秀品質(zhì)。2. 繼續(xù)練習用比較快的速度閱讀課文，讀后能說出每一部分的主要內(nèi)容。3. 練習給每一部分課文加小標題?！窘虒W重點、難點】用較快的速度閱讀課文，說出每一部分的主要內(nèi)容?！窘虒W時間】1課時。【設計理念】本文雖是略讀課文，但由于篇幅較長，可以安排一課時完成。教學中要練習用比較快的速度閱讀課文，培養(yǎng)學生的自讀能力。先通讀課文，用比較快的速度默讀課文，了解雨來是哪里人，生活在哪個年代？為什么稱他是小英雄？大體了解課文主要講了什么。全文研讀時一部分一部分地閱讀、思考，特別重點理解我們是中國人，我們愛自己的祖國這句話。在全面理解課文內(nèi)容的基礎上給各部分加小標題。最后進行總結擴展：觀看情景??；建議學生找來管樺小說的原著讀一讀?！窘虒W過程】一、激發(fā)情感，釋題引疑1、課件演示：小雨來與鬼子斗爭的片斷。問：你們想認識這位小英雄嗎？2、出示課題：(1) 理解課題：齊讀課題你從中知道了什么？小——指的是雨來的年齡小，是一個少年。英雄——指的“是雨來的特點。雨來——課文中的主人公。課題表現(xiàn)出文章的中心——英雄。(2) 引導到學生質(zhì)疑：看到課題后，你還想知道什么？（為什么稱雨來是小英雄？）（從課文中的哪些地方可以看出雨來是一位小英雄？）
一年級朗文下冊1B 教材 Chapter 1 A
l 通過學習該單元的內(nèi)容，學會正確讀出小動物的單詞如：dog cat bird rabbit hamster turtle;l 掌握基本句型： What is this ? It is a .... What isthat ? It is a .....l 學會用英語來描述自己喜歡的寵物。l 培養(yǎng)學生仔細觀察圖片，獲取關鍵信息的能力；l 培養(yǎng)辯證思維及策劃、合作和交流的能力。l 激發(fā)學習英語的興趣，同時培養(yǎng)積極參與、樂于合作、大方交流的情感態(tài)度。
人教版新課標小學數(shù)學一年級下冊兩位數(shù)減一位數(shù)和整十數(shù)（不退位）教案
一、教學內(nèi)容：兩位數(shù)減一位數(shù)和整十數(shù)（不退位）（課本第67頁）。二、教學目標：1、知識與技能：讓學生經(jīng)歷探索兩位數(shù)減一位數(shù)和整十數(shù)（不退位）的計算方法的過程，掌握計算方法，能正確地口算。2、過程與方法：讓學生經(jīng)歷自主探索、動手操作、合作交流等方式獲得新知的過程，積累數(shù)學活動的經(jīng)驗，體會數(shù)學知識與日常生活的密切聯(lián)系，增強應用意識。3、情感態(tài)度與價值觀：進一步培養(yǎng)學生學習數(shù)學的熱情，以及積極思考、動手實踐并與同學合作學習的態(tài)度。三、教學重點：掌握兩位數(shù)減一位數(shù)和整十數(shù)（不退位）的口算方法。四、教學難點：理解算理，把握兩位數(shù)減一位數(shù)與兩位數(shù)減整十位數(shù)在計算過程中的相同點與不同點。五、教具準備：課件、題卡、等。六、教學過程：（一）、創(chuàng)設情境，提出問題。
初中歷史與社會人教版九年級下冊《地球一小時 活動》教材教案
地球一小時（Earth Hour）是世界自然基金會（WWF）應對全球氣候變化所提出的一項倡議，希望家庭及商界用戶關上不必要的電燈及耗電產(chǎn)品一小時。來表明他們對應對氣候變化行動的支持。過量二氧化碳排放導致的氣候變化目前已經(jīng)極大地威脅到地球上人類的生存。公眾只有通過改變?nèi)蛎癖妼τ诙趸寂欧诺膽B(tài)度，才能減輕這一威脅對世界造成的影響。地球一小時在3月的最后一個星期六20:30~21:30期間熄燈?；顒佑蓙恚骸暗厍?小時”也稱“關燈一小時”，是世界自然基金會在2007年向全球發(fā)出的一項倡議：呼吁個人、社區(qū)、企業(yè)和政府在每年三月最后一個星期六20：30~21：30期間熄燈1小時，以此來激發(fā)人們對保護地球的責任感，以及對氣候變化等環(huán)境問題的思考，表明對全球共同抵御氣候變暖行動的支持。這是一項全球性的活動，世界自然基金會于2007年首次在悉尼倡導之后，以驚人的速度席卷全球，大家都來參加這個活動。[1] “地球1小時”活動首次于2007年3月31日在澳大利亞的悉尼展開，一下子吸引了超過220萬悉尼家庭和企業(yè)參加；隨后，該活動以驚人的速度迅速席卷全球。在2008年，WWF（中國）對外聯(lián)絡處透露，全球已經(jīng)有超過80個國家、大約1000座城市加入活動。2013年，包括悉尼歌劇院、帝國大廈、東京塔、迪拜塔、白金漢宮在內(nèi)的各國標志性建筑也在當?shù)貢r間晚八點半熄燈一小時。[2] ，其中包括巴勒斯坦、法屬圭亞那、加拉帕戈斯群島、盧旺達、圣赫勒那島、蘇里南、突尼斯等首次參與“地球一小時”的國家和地區(qū)。在中國，北京鳥巢、水立方、世貿(mào)天階等標志性建筑同時熄燈，同一時段，從上海東方明珠到武漢黃鶴樓，從臺北101到香港天際100觀景臺，中國各地多個標志性建筑均熄燈一小時，全國共有127個城市加入“地球一小時”活動。
初中化學人教版九年級下冊《實驗活動7溶液酸堿性的檢驗》教案
1.自己選擇植物的花瓣(牽?；ā⒃录净?、蔬菜(紫卷心菜、胡蘿卜) 在研缽中搗爛，加入酒精(它有消毒作用，可使制得的指示劑長期 保存)浸泡，用紗布將浸泡出的汁液過濾或擠出，就得到指示劑， 2.把制好的指示劑裝入試劑瓶，貼上標簽備用。 把食醋、稀鹽酸、稀氫氧化鈉、澄清石灰水，分別滴在兩個 白色點滴板上，用石蕊、酚酞分別滴在上述溶液上，通過顏 色變化檢驗它們的酸堿性。 用玻璃棒分別蘸取上述溶液，滴在pH試紙上，然后對照標準 比色卡比較，得出pH值，也就是酸堿度。 把上述溶液滴在白色點滴板上，用滴管吸一下你自制的指示劑，滴在滴板的溶液里，觀察顏色變化，每用一種指示劑，換一下滴板的溶液。 把所得到顏色變色變化的信息和pH值數(shù)據(jù)填入教材第70頁的表中。 3.取少量土壤樣品，將土壤樣品與蒸餾水按1∶5的質(zhì)量比在燒杯中混合， 充分攪拌后靜置，用玻璃棒蘸澄清的液體，滴在pH試紙上，然后對照 標準比色卡記錄讀數(shù)。
人教版新目標初中英語七年級下冊How was your weekend教案2篇
Teaching Goal:1. General aims:Talk about recent past events2. Particular aims:A. Language Focus.Talk about recent past events and think of the past events.B. Language goalsHow was….?It was …What did …do over the weekend?C. Language structures:(1). How was your weekend? I was great. Pay attention to no form.(2). What did you do over the weekend? I played soccer. We went to the beach.D. Useful words and phrases:Words: was, did, went, beach, over, project, test, wasn’t, false, number, geography, spend, week, most, mixture, their, had, little, cook, read, saw, change, everyone, sit, sat, no, anythingPhrases: did one’s homework, played soccer, cleaned my room, went to the beach, played tennis, went to the movies, on Saturday morning, over the weekend, cook … for, what about, do some reading, have a party, talk show, go shoppingE. Grammar language:Present simple past tenseRegular and irregular verbsF. Learning strategies:Tour and holidaysG. Interdiscipinary:H. Emotion and manner:Teaching time: 5 periodsTeaching procedures:Period One教學步驟、時間 教師活動 學生活動 媒體應用Step 1Free talk 3’ Ask some questions like:Who’s on duty today?What’s the weather like? Answer and talk about something.讓同學們回答下列問題1. Do you like weekend? (Let some students answer)It takes them three minutes to talk about the question.2. Why do you like weekend? (let the students answer) Most of the students like the weekend此時教師用漢語問：“在周末期間問你干了什么?這句話用英語這么回答?Let the students guess.At last the teacher give them right answer3. What did you do over the weekend?(板書、學習)
人教版新目標初中英語七年級下冊Where is the post office教案2篇
Period 2 (3a----Section B 2c)Preview(Pre-task): Key points: What laAdd another information about their pen pals----their language on the cardnguage does she/he speak?She/He speaks....Does she/he have any brothers and sisters? Does she/he speak English?Preview(Pre-task): Add another information about their pen pals----their language on the cardKey points: What language does she/he speak?She/He speaks....Does she/he have any brothers and sisters? Does she/he speak English?Step 1 Revision1.Revisionand dictation of the new words 2.Revise the drills they learned yesterday.(by pairwork and grammar exercise)Step 2 Leading-inT has a conversation with one student. The conversation is following:---Do you have a pen pal?---Yes, I do.---What's your pen pal's name? ---His/Her name is....---Where is your pen pal from? ---He/She is from...---Where does he/she live? ---He/She lives in....---What language does he/she speak?He/She speaks...Write the new words on the Bb. They are following: EnglishChineseJapaneseFrenchStep 3 LearnLearn the new words with the whole class.Finish 3a with the students3b Pairwork T still does an example with one student Then the Ss practise in pairs. The example is following:--Curry Muray is my pen pal. He is from the United States.---What language does he speak?
人教版新目標初中英語七年級下冊Don’t eat in class教案2篇
Don’t fight. =You can’t fight. （板書，教讀）教師把這些句子板書在黑板上，并請學生大聲整齊地讀祈使句和“can’t”句型，并讓學生注意兩種句型表達形式的不同和轉換,“Don’t …=You can’t…”;并對學生說：These are our school rules. （板書，教讀） You can’t break the school rules. Don’t break the school rules.（板書，教讀）步驟3 :Practicea. T: Now, each of the students is breaking one of these rules.Please finish 1a.學生看圖，完成1a的內(nèi)容，檢查答案并大聲朗讀校規(guī)。b. 聽錄音，完成1b，選出四位學生都違反了哪條校規(guī)；聽之前，學生要讀會英文名。c. 請兩位學生朗讀1c部分的句型；要求學生兩人一組對話表演，SA扮演外校轉來新生，SB告知本校校規(guī)。（學生可經(jīng)過討論，多說出他們想到的校規(guī)，不必只限于書上；教師應給予幫助）2) 第二課時（2a~4）步驟1 :warming up of revisionT: What are the rules at your school?學生使用“can”或祈使句表達各條校規(guī)；其中老師可引出“eat in the cafeteria outside”的表達。步驟2 :Practicea.T: Christina is an exchange student. She doesn’t know the rules. Let’s listen, what activities they’re talking about?學生聽第一遍時，完成2a；第二遍時，完成2b；b. 請學生領讀2c部分，看著2a完成的表格，理解2c活動的要求；分成小組針對2a進行問答；
人教版新目標初中英語七年級下冊I ’d like some noodles教案
教學過程Step 1: warming-up Sing a song---------“food and drink” Step 2: Revision1 Dictation2 Revise: What kind of noodles would you like?I’d like …What size bowl of noodles would you like?I’d like…Step 3: Presentation1 show pictures of food, ask students say the words.2 Students read the newspaper ad in 3a. Fill in blanks with words in the box. Then read the ad together, the teacher explains some difficult language points.3 Check the answers Step 4 PracticeAsk students to finish 3b in the same way according to 3a. Students read the short passage and fill in the blanks .At last, check the answers.Step 5 productionAsk students to write their own ad for dumplings, noodles, drinks, and other foods they know. Then ask students to read their partner’s ad. Then order food and drink from their partner.Step 6 Home workGroup work – make an ad about “food and drink”
人教版新目標初中英語七年級下冊It’s raining教案2篇
1 Each group choose one place to describe and what you are doing in it Choose one place, and describe what they are doing 2 Move around the room and give suggestions Talk about it and write it down 3 Ask one to show their works and act it Choose one of each group to make a report 4 Evaluate the best group and the best reporter Choose the best one Homework Ask your friends their ideal place and write about it教學反思：新課程標準中強調(diào)學生在課堂中的主體地位，在綜合課中他們的主體地位就更加突出。在各個活動中給不同程度的學生不同層次的任務，讓各層面的學生都有表現(xiàn)發(fā)揮的機會，從而產(chǎn)生對英語的興趣。使用照片圖片多媒體來輔助教學，效果更好。同時讓了解其他國家風景，風俗的同學介紹ideal place，增加學生的背景知知識，實現(xiàn)跨學科交流的目的。教案點評：采用任務型教學模式，在各個活動中給不同程度的學生不同層次的任務，讓各層面的學生都有表現(xiàn)發(fā)揮的機會，從而產(chǎn)生對英語的興趣。使用照片圖片多媒體來輔助教學，效果更好。讓了解其他國家風景，風俗的同學介紹ideal place，增加學生的背景知識，實現(xiàn)跨學科交流的目的。
人教版新目標初中英語七年級下冊Where is your pen pal from教案
2.1Match the country with the language.Step II Reading3a? let the students read the letter fast and answer the questions.? Let the students ask more questions about the letter as possible as the can.Step III Writing3b.Step IV. Pairwork2cStep V Listening2a, 2bStep V. HomeworkExercises book(1) P3Exercises book (2) P3Period FourStep I . Dictate the words and sentences in Unit1.Step II. Self-checkStep III. Check the answers for Exercises book in the unit.Step IV. Home workRevise and preparation for unit 2.教學反思：通過本單元的學習，學生基本可以談論人們的國籍，居住城市及其所說的語言，通過書信方式去介紹自己并尋找筆友。但在涉及到國外的一些城市時，學生對這方面的知識相對欠缺，能介紹的城市并不多，也反應出學生課前預習不充分，這跟學生學習條件也有關，大多數(shù)學生無法通過網(wǎng)絡獲取所需信息。因此，在以后的教學中要多指導學生通過計算機網(wǎng)絡獲取信息，拓寬知識面。
人教版新目標初中英語七年級下冊Where did you go on vacation教案
句型: Where did you go on vacation? I went to summer camp．Did she go to Central Park？Yes，she did．No, she didn’t語法：一般過去時特殊疑問句、一般疑問句及肯、否定回答。課時安排4課時第一課時：Section A：la，1b，lc，2a，2b，2c 第二課時：Section A：3a，3b，4第三課時：Section B：1，2a，2b，2c第四課時：Section B：3a，3b，3c，4 and Self Check第一課時教學目標掌握描寫假期生活的形容詞。假期里自己所做事情的簡單表達。談論假期做的事情及當時情況。談論假期時旅游的天氣，旅游者以及食物等。教學過程一、導入播放一首英文歌曲：Let’s travel 說明：通過讓學生聽節(jié)奏歡快迪斯尼英語歌曲Let’s travel.引入本節(jié)課談論的話題vacation and travel. 讓歌曲使學生的思維活躍，增強課堂氣氛，激發(fā)學生提高學習英語的興趣。T：How is the trip ?Ss : It’s pretty good/ happy/exciting /relaxing/busy/dangerous/ fantastic說明：這個問題是為了操練形容詞。建議讓多個Ss作答。鼓勵他們用不同的形容詞。上述個別形容詞本應在第二課時中出現(xiàn)，但可以在warming-up中第一次非正式出現(xiàn)。這些形容詞也可在老師的評價語中適時出現(xiàn)，以加深學生對詞匯的印象。
人教版新目標初中英語七年級下冊Why do you like koalas教案2篇
單元整體說明（一）單元教材分析本單元的核心話題是描述動物和表達個人喜好，以及句式why do you like…? Because…。這也是本單元的教學重點。通過本單元的學習，學生應能較流利地運用所學詞匯和句型描述動物，表達個人喜好。（二）單元知識結構1．詞匯動物名稱 tiger, elephant, koala, dolphin, etc．詞匯描述性形容詞: smart, cute, ugly, clever, shy, etc．國家名: Australia, South Africa2．句型Why do you like koala hears? Because they are cute．Where are pandas from? They're from China．What animals do you like? I like dolphins．（三）單元整體目標1．Master the vocabulary2．Master and use: Why do you like koalas? Because they am cute．Where are pandas from? They're from China．What animals do you like? I like dolphins．（四）單元教學重難點一覽（五）單元學情分析學生此前已經(jīng)學過由why, where, what 引導的特殊疑問句句型，具有了學習本單元知識的認知前提。形形色色的動物能激發(fā)學生的好奇心，產(chǎn)生了解它們的欲望，這有利于本單元知識的教學和學生學習興趣的培養(yǎng)。
人教版新目標初中英語八年級下冊Have you ever been to an amusement park教案
（1）Have you ever been to …? Yes, I have. / Yes, I have ever been to …No, I haven’t. / No, I have never been to …（2）When did you go there? I went there last year. （3）I have never been to a water park. Neither have I. I have ever been to an amusement park. So have I. （4）How long have you been studying English? I’ve been studying English since nine o’clock. I’ve been studying English since I came back home. I’ve been studying English for five hours. （5）What’s that? It’s an amusement park in Japan. I’ve never been to an amusement park like it before. It’s fun to learn another language. Let’s go tonight. Isn’t this great?space museum, amusement park, water park, South America, Peru, Holland, European culture, tour guide, flight attendant, musical instrument, more than, be from, get to, take lessons, neither, discover, graduate, change
人教版新目標初中英語八年級下冊What should I do教案2篇
說明：在幫Li Lei提建議的同時，教育學生如何學好英語。第三課時教學目標1. 語言目標：a) 詞匯: Original, in style, haircut, the same as.b) 語言結構:My friend wears the same clothes and has the same haircut as I do.2. 能力目標:大多數(shù)學生能夠談論自己喜歡哪種服裝，提高查找信息的能力。3. 情感目標:學會如何與朋友相處，要有自己對時尚的看法。教學重點掌握一些重要詞匯。教學難點學會談論問題，并能提出書面建議?！艚虒W突破首先針對Erin的問題，提出個人的建議，模仿2c部分的對話展開雙人交際Pair-work；聽老師誦讀3a部分的信件，并找出LEFT OUT的問題所在；學生完成3b部分的內(nèi)容，給Left Out提出書面的建議；學以口頭形式提出自己目前存在的某個問題，講給大家聽，讓同學們給自己提出一個建議，并作筆錄；學生兩、三個人分成一組，隨意性地進行口語交際，談論P14的第4部分的某個問題，相互交換意見。
人教版新目標初中英語八年級下冊If you go to the party, you’ll have a great time教案2篇
區(qū)分賓語從句、定于從句和狀語從句賓語從句和狀語從句，都叫做主從復合句。賓語從句主要是中考必考的，是初中階段必掌握的從句，賓語從句主要是掌握三要素，所謂賓語從句，就是賓語在主從復合句當中充當賓語的一個句子，叫做賓語從句。主句的謂語動詞是及物動詞，后面如果是詞或者是短語的話，是簡單句，如果是句子的話，肯定是賓語從句。I know that he good at English.就是賓語從句，三要素，一要素是要注意連詞，連詞一共學了三類連詞，一類連詞是that口語當中可以省略，就像剛才說的那一句，I hear he is good at English.還有疑問代詞、疑問副詞，how where when，疑問代詞、疑問副詞。還有一類連詞weather是否的意思，不是狀語從句當中的如果，這一定要和如果區(qū)分開，這是是否。I don't know if he interested at English。賓語從句要注意if是連詞。第二要素是語序，要用陳述舉語序。比如說你家有幾口人，我們都說How many people are there in you family?但是這是簡單句，一旦說成賓語從句，你可以告訴我你家有幾口人嗎？Could you tell me how many people there are in you family ?
人教版新目標初中英語八年級下冊It’s a nice day, isn’t it教案2篇
"Hello! Welcome to English class! Introduce yourself. Meet your new classmates." That's what the teacher says. What do you say? "Oh no!" It can be difficult talking to new people. But it can be fun, and you can make friends. How do you do it? Make small talk. Small talk is polite conversation. "Wang Nan is a great pingpang player, isn't she?" "I'd love to meet her, wouldn't you?" "It's been raining a lot, hasn't it?" Tag questions are a form of polite speech. To make small talk successfully, you should know how to make them. You should also know what topics to talk about. Try to learn this unit carefully. The next time you're in English class, you'll find out. Making small talk's easy, isn't it? (“你好！歡迎你！請做一下自我介紹。認識一下你的新同學?！蓖ǔＴ谡n上老師會這樣說。你會說什么呢？“噢，不！”與陌生人談話太困難了。但是這也很有意思，并且你還能交到朋友。你該怎么做呢？閑聊。閑聊指得是禮貌的對話。“王楠是一個很棒的乒乓球運動員，不是嗎？”“我希望自己能認識她，你呢？“今年的雨水很多，不是嗎？”反意疑問句是一種禮貌用語。為了使得談話成功，你應該知道怎樣去進行閑聊。你還應該知道與不同的人該談論什么樣的話題。認真的學習這個單元吧，下次在英語課上，你會發(fā)現(xiàn)與大家展開談話是一件很容易的事情，不信我們來試試。)
人教版新目標初中英語八年級下冊He said I was hard-working教案2篇
This activity introduces some new vocabulary and provide oral practice using the target language.Task 1 . Ask four students to stand in front of the class, and the teacher asks them the following questions as a reporter.1.What are you going to do when you grow up?2.What are you going to do next week?3.What are going to do after school?The students will give different answers, then ask a good student to report what they said.I am going to e a doctor.What did she say?----------She said she was going to be a doctor.I am going to have a party on Friday night.What did he say?-------He said he was going to have a party on Friday night.I am going to do my homework.What did she say ?------ She said she was going to do her homework.I am going home after school.What did she say?-----She said she was going home after school.Say In this unit we are going to learn to use words like to report what someone said.Task 2. Read the instructions. Then ask a student to read the four questions. And write the words on the Bb. Explain what soap opera is.Task 3. Ask the students to Look at the pictures, point out the TV screens in the picture. Ask one girl to read what Marcia said.What did Marcia say? She said She said she was having a surprise party for Lana on Friday night. Repeat the other pictures in the same way.Activity3. Listen and number the pictures in activity 1a.
人教版新目標初中英語八年級下冊How long have you been collecting shells教案2篇
Step Ⅱ Show the new words on the screen and teach the new words. Read the new words to students and ask them to repeat.Step Ⅲ 3aThis activity introduces new vocabulary and provides reading practice using the target language.In this activity first look at the four pictures.T: What can you see in the pictures?Ss: Four snow globes.T: Right. There are four snow globes in the pictures. And what are they?Ss: They are a monster, two polar bears, two penguins and a birthday cake.Write these words on the blackboard: snow globe; monster; polar bear; penguin and birthday cake. Read them to the class and ask students to repeat each one. Make sure students understand each word.Use a computer to show the E-mail message on the screen and read the message to students.Get students to read the e-mail on their own, and then draw lines connecting each snow globe and its description.Correct the answers.AnswersA line should connect each snow globe picture with the words that describe it in the letter.Step Ⅳ 3bThis activity provides writing practice using the target language.First review Activity 2a on Page 47.Then ask students to complete the message according to Activity 2a.Some partial sentences are given to students. Write about one person's collection.When students work, walk around the room checking the progress and offering help as needed.When they finish, ask some students to read their messages to the class.
人教版新目標初中英語八年級下冊What were you doing when the UFO arrived教案2篇
(一).知識方面: 1.培養(yǎng)學生能運用過去進行時來描述、談論過去某個時間正在發(fā)生的事情或動作的意識和能力，能就過去某個時間正在發(fā)生的動作做出正確的描述。 2.培養(yǎng)學生的想象力和角色扮演的合作能力。 3.培養(yǎng)學生講述過去發(fā)生的事情經(jīng)過的能力。能正確運用一般過去時來講述故事。 (二).技能方面: 1.本單元的語言目標是Talk about past events and tell a story（談論過去的時間和講述一個故事），圍繞這一目標，要涉及句型： What were you doing when the UFO arrived? ----I was sitting in the barber’s chair. The barber was cutting my hair. 因此必須學習standing、studying、cleaning、sleeping、cooking、making、eating、cutting、等表示地點的詞，以便為上述句型提供語言材料。2.學習過去進行時的有關知識。Was/were+現(xiàn)在分詞，是該時態(tài)的表達式。 3.在學習過程中，要區(qū)分The boy was walking down the street when the UFO landed.和While the boy was walking down the street, the UFO landed.這兩種由when和while引導的狀語從句的句型結構。注意它們的不同。