约1750字。

　　Unit3 What were you doing when the UFO arrived?导学案
　　Section A
　　学习目标：1.谈论过去发生的事情
　　2.学会讲故事
　　3.热爱科学，探索科学
　　学习重点：1.词汇UFO,alien,bathroom,land,imagine,strange,follow,amazing
　　2短语barber shop,in front of,get out of,cut hair,take off,have an unusual experience
　　3.句型You can imagine how strange it was!
　　Isn't that amazing!
　　学习难点：1.过去进行时的用法
　　2.when和while的用法
　　自主学习：
　　一、语法导航：过去进行时
　　1）过去进行时由“was/were+动词-ing”构成，表示在过去某一时刻或某一段时间正在进行的动作。这一特定的过去时间除有上下文暗示以外，一般用时间状语来表示。如一些表示时间的短语：at nine o'clock last Sunday morning,last night,at this time yesterday,at noon yesterday以及when和while引导的时间状语从句。如：
　　What were you doing when the UFO arrived?I was sleeping.
　　2）过去进行时的否定式在was/were后加not,wasn't=was not,weren't=were not,一般疑问句直接把was/were提前,如：He wasn't cooking at that time yesterday.
　　Were you doing your homework when your mother came back from work?Yes,I was.
　　一般过去时与过去进行时用法的比较：一般过去时表示在过去某个时间发生过的动作或存在的状态，而过去进行时则表示在过去某一时刻或某一段时间正在进行的动作。如：
　　David wrote a letter to his friend last night.（信写完了。）
　　David was writing a letter to his friend last night.(信不一定写完。)
　　用所给动词的适当形式填空。
　　1.I_________(do)my homework at nine yesterday evening.
　　2.Mr Brown________(read)a newspaper at seven yesterday morning.
　　3.He__________(watch)TV when his father came back.
　　4.what_____you______(do)at noon yesterday?I________(have)lunch.
　　5.______they_______(play)basketball at eight last Friday?No,they_____.
　　6.I___________(sleep)when he______(come)in.
　　根据汉语提示写出英语单词或词组。
　　不明飞行物______外星人_______着陆_______当…的时候_______
　　在浴室洗澡_____________________在卧室里睡懒觉_____________________
　　在厨房里做饭_____________________在理发店理发_______________________
　　刚洗完澡出来_____________________站在图书馆前面______________________
　　参观航天博物馆____________________通过电话交谈____________________
　　Pairwork:
　　What were your family doing at 7:00 last Sunday evening?Fill in the chart and map a conversation.
　　Family member What were/was…doing at 7:00 last Sunday evening?
　　I 
　　Father 
　　Mother 
　　Sister/Brother 
　　Pairwork
　　A UFO landed in a small town.Look at the pictures and talt what were the people doing when the UFO arrived.
　　1                     2              3                4               5                  6
　　A:Where was he/she when the UFO arrived?B:He/She was in…
　　B:What was he/she doing at that time?B:He/She was…
　　疑难解析：when和while
　　1）When“当…的时候”。既可指时间点，又可指时间段，从句中可用延续性动词，也可用非延续性动词。例如：It was snowing heavily when the plane took off.
　　While“当…的时候”；“在…期间”。指时间段，从句中必须用延续性动词。例如：
　　While I was walking on the street,I met Tom.
　　While Li Lei is doing his homework,his father is cooking dinner.
　　用when和while填空。