七年级下册数学《二元一次方程组的解法——代入法》.docx

1.现在进行时（ThePresentProgressiveTense）1)现在进行时表示现在（说话瞬间）正在进行或发生的的动作。如：Thestudentarelisteningtotheteacher.HeiswatchingTVnow.现在进行时也可表示当前一段时间内的活动或现阶段正在进行的动作。Weareworkingonafarmthesedays.Imwritingabookthismonth.2)构成：be(am/is/are)+v-ing。以动词work为例，现在进行时的肯定式、否定式、疑问式和简略答语如下：肯定式Iamworking.Youareworking.He/She/Itisworking.We/You/Theyareworking.否定式Iamnotworking.Youarenotworking.2.He/She/Itisnotworking.We/You/Theyarenotworking.疑问式和简略答语：AmIworking? Areyouworking?Yes,youare.Yes,Iam.No,youarenot(arent)No,Iamnot.Ishe/she/itworking?Areweworking?Yes,youare.Yes,he/she/itis.No,he/she/itisnot(isnt).No,youarenot(arent)Areyouworking?Aretheyworking?Yes,weare.Yes,theyare.No,wearenot(arent)No,theyarenot(arent).3)动词-ing形式的构成：一般在动词原形末尾加-ing.gogoingaskaskinglooklooking以不发音字母e结尾的动词，先去掉e，再加-ing.writewritingmakemakingtaketaking以重读闭音节结尾的动词，如果末尾只有一个辅音字母，应先双写这个字母，再加-ing。getgettingsitsittingputputtingrunrunningbeginbeginning以ie结尾的重读开音节动词改ie为y，再加-ing。diedyinglielyingtie-tying2.Whatareyoudoing?ImwatchingTV.你在干什么？我在看电视。Whatshedoing?Hesdoinghishomework.他在干什么？他在做家庭作业。Whatsshedoing?Shesreading.她在干什么？她在看书。I、词汇（15分）A、写出下列单词的现在分词和三人称单数形式。(10分)1.swim_2.take_3.run_4.go_5.buy_6.help_7.listen_8.dance_9.clean_10.talk_11.visit_12.have_13.begin_14.arrive_15.find_16.sing_17.sleep_18.eat_19.have_20.pass_II、句型转换。（10分）1.Heisdoingsomehousework.（变一般问句）hedoinghousework?2.Sheiswritingaletter.(对划线部分提问) isshe ?3.Areyouwaitingforthebus?（作否定回答）No,I .4.Iwanttogothereat6:45.(对划线部分提问)。_ _youwanttogothere?5.HewritesEnglisheverymorning.(用now改写句子)。He Englishnow.过去进行时（ThePastProgressiveTense）1.用法：过去某个时间正在发生的动作 He was cooking at six last night. 昨天晚上六点，他正在做饭。过去某段时间正在发生的动作 I was staying here from March to May last year.去年从3月到5月，我一直呆在这里。2 .与过去进行时连用的时间状语，常见的有 at nine last night/ at that time= then/at this time yesterday /或有when the teacher came in/ while he was reading的提示(1) 过去进行时的构成：was/ were doing(2) 过去进行时表示在过去某一时刻或某一段时间正在进行的动作。肯定句：主语 + was/ were doing + 否定句：主语 + was/ were + not doing + 一般疑问句：Was/ Were + 主语 + doing + ？特殊疑问句：疑问词+ was/ were + 主语 + doing + ？时态现在进行时过去进行时用法表示现在正在进行的动作表示过去某个时刻正在进行的动作结构is/am/are + doingwas/were + doing例句I am having an English classI was having an English class.请比较 He watched TV last night. （过去时间last night, 用一般过去时） He was watching TV at nine last night. (过去时间last night+点时间at nine, 用过去进行时)at the time of 在. 的时候 （常用于过去进行时）【2013浙江杭州4】Sally took a photo of her friends while they _ computer games. A. play B. are playing C. have played D. were playing 【2013黑龙江绥化3】My uncle _ books in the room at this time yesterday.A. was seeing B. is reading C. was reading【2013黑龙江齐齐哈尔3】What _ you _ when the captain came in? A. are; doing B. did; do C. were; doing巩固练习：用所给动词的适当形式填空1. Now Jims sister _(read) newspapers.2.He _(watch)TV at nine last night.3.He _(watch)TV last night.4. What _the twins _(do) then?5. _Lily _(draw) a cat when the teacher came in ? No, she _6. _you _(have) supper at that time?7. Jack _(not read) a book at nine yesterday evening.8. Now Jim _(play) basketball on the playground（操场）.9. What _ he _ (do) at nine oclock last night.10. They _ (listen) to the music at that time.11. When the teacher came in, the students _ (read) the text.12. We _ (watch) TV when suddenly the telephone rang.13. Her mother _(cook) while her father was watching TV.