仁爱八年级英语Unit 1 Past and present课件

2021-04-13 课件

  一. 教学内容:

  Unit 1 Past and present Graar

  二. 教学目标:

  掌握Unit1的语法: Present perfect tense 现在完成时的用法

  (一)基本概念

  1、定义

  现在完成时用来表示之前已发生或完成的动作或状态,但它的影响现在还存在;也可表示持续到现在的动作或状态。

  2、构成: have (has) +过去分词。规则变化的过去分词与过去式的变化一样,在动词词尾加ed; 不规则变化的过去分词见不规则动词表,需要同学们记忆。

  3、句型:

  现以see the fil为例将现在完成时的肯定句,否定句和疑问句列表如下:

  肯定句:I/u/We/The have seen the fil. He/She /It has seen the fil.

  否定句:I/u/We/The have nt/ haven’t seen the fil.

  He/ She/It has nt/hasn’t seen the fil.

  疑问句:Have I/u/the seen the fil? es, u/ we/I/the have. N, u/ we/I/the haven’t.

  Has he/she/it seen the fil? es, he/ she/ it has. N, he/ she/ it hasn’t.

  (二)用法:现在完成时既涉及过去,又联系现在。

  用法一:表示过去发生或已经完成的某一动作对现在造成的影响或结果。常与ust(刚刚),alread(已经),never(从来没有),ever(曾经),befre(以前),et(仍然),nce(一次),twice(两次),an ties(很多次),hw an ties(多少次),s far(迄今为止),during the past(last)three ears(最近三年来)等连用。

  ※ 副词的位置:①ust常用于肯定句中,放在have / has后,He has ust ce .

  ②never表示否定, 放在have / has后, He has never visited the Great Wall.

  ③ever用于疑问句中,句型为: Have / Has+主语+ever +过去分词?“……曾经……过吗?”用于询问某人过去的经历。Have u ever been t the far?

  ④befre用于句末,The wan has never heard f that befre.

  ⑤et 用于句末或nt 之后. Has the train arrived et? N, nt et.

  ⑥alread用于肯定句, have / has 之后或句末.We have alread finished it.

  ⑦s far用于句首或句末. S far, we have visited the n.

  用法二:表示过去已经开始,一直延续到现在的动作或状态。时间状语有:

  (三)现在完成时态中可以和表示一段时间的状语(fr,since,hw lng, all ne’s life)连用的动词必须是表示延续的情况或动作的动词,即延续性动词。如:be,have,nw,live,wr,stud,learn,teach,eep,spea,tal,draw,wait,wear,wal,sleep,drive,write,d,clean等。

  I have been a teacher fr nearl 20 ears. Hw lng has he lived here?

  (四)延续性动词的现在完成时可和包括“现在”在内的(到说话时仍未结束)表示一段时间的状语连用。如this rning,tda,this wee,these das

  He has been t Beiing three ties this ear.

  He has written tw letters this rning.(说话时间在上午)

  He wrte tw letters this rning.(说话时间在下午或晚上)

  (五)英语中还有一些动词的意义决定它们所表示的动作不能延续,只是一瞬间

  就结束的动作,这类动词叫做“非延续性动词”,常见的有:ce,g,arrive,reach,see,hear,clse,pen,leave,begin,start,lse,bu,fall,in,die,get up,bece,brrw,lend,find,finish,receive等。这些动词可用于现在完成时,说明某个动作的结果还存在,但不能和表示一段时间的状语(hw lng,fr,since)连用。

  He has ce bac.(√)

  He has ce bac fr tw hurs.(×)

  ※ 但在否定句中,非延续性动词也可用表示一段时间的状语来修饰,如

  I haven’t heard fr  father fr a lng tie.

  We haven’t seen hi since 1999.

  (六)当终止性动词(非延续性动词)与表示一段时间的状语(hw lng,since,fr,all ne’s life)相矛盾时,改正错句的方法有如下几种:

  (1)用副词ag把现在完成时的句子改为一般过去时.

  He has ce bac fr tw wees.(错)

  改为: He cae bac tw wees ag.(正)

  I have lst  bie fr ten das. (错)

  改为: I lst  bie ten das ag. (正)

  (2)用“It is / has been+时间+since+一般过去时态”句型来改写。

  He has ined the League fr 3 ears. (错)

  It is 3 ears since he ined the League.(正)

  I have bught the b fr 5 das. (错)

  It is 5 das since I bught the b. (正)

  He has died fr 20 ears. (错)

  It is 20 ears since he died. (正)

  (3)用“时间+has passed+since+一般过去时态”句型来改写。

  He has left he fr 20 ears.

  改为: Twent ears has passed since he left he.

  He has lst his pen fr 2 das.

  改为: Tw das has passed since he lst his pen.

  (4)用系表结构来改写.

  He has died fr 20 ears.

  改为: He has been dead fr 20 ears.

  The factr has pened since 1999.

  改为: The factr has been pen since 1999.

  Hw lng has he left?

  改为: Hw lng has he been awa?

  (5)用相应的延续性动词替代非延续性动词。

  He has bught the b fr tw wees.

  改为: He has had the b fr tw wees.

  常见的相应转换形式如下:

  brrw / lend→eep, bu→have, finish / end→be ver, arrive /ce / g / ve / reach /get t→be in /at / be here /be there, begin / start→be n , pen→be pen , clse→be clsed, die→be dead , leave→be awa(fr), g t schl→be in schl / be a student, get up→be up, fall asleep→be asleep , fall ill→be ill, get t nw→nw, lse→be lst, bece→be, return / ce bac / get bac→be bac, in→be in / be a…eber, in the ar→be in the ar /be a sldier, receive / get a letter→have a letter , catch / get a cld→have a cld, begin t stud→stud

  他参军已有三年。

  He has ined the ar fr three ears.(错)

  改为:

  He has been in the ar fr three ears / since three ears ag.

  He has been a sldier fr three ears / since three ears ag.

  He ined the ar three ears ag.

  It is three ears since he ined the ar.

  Three ears has passed since he ined the ar.

  (1)He cae t ur village tw ears ag.=He ur village since tw ears ag.

  (2)He left he three das ag. =He he fr 3 das.

  (3)I bught the watch 2 wees ag. =I the watch since 2 wees ag.

  (4)It is 5 das since I brrwed the b. =I the b fr 5 das.

  (5)The fil has begun. = The fil fr half an hur.

  (6)I gt t nw hi 10 ears ag. =I hi fr 10 ears.

  (7)There is a factr. =There a factr fr 20 ears.

  (8)Our schl pened in 1960. =Our schl since 1960.

  (七)现在完成时中应注意的几个问题

  1. have been t 和have gne t的区别

  have been t 强调“去过”,现已不在那里,如:

  He has been t the USA three ties.

  他到美国去过三次。(过去“到美国”,现在已“不在美国”)

  have gne t主要强调的是“去了”,现在人不在说话的'现场,如:

  —Where’s ur ther? —你妈妈在哪?

  —She has gne t the hspital. —她去医院了。

  2. have been t 和have been in的区别

  have been t强调人“已回到原地”,后面可接表示“次数”的状语。

  eg. ① She has been t Shanghai nl nce.

  ②—Hw an ties has he been there? —He’s been there an ties.

  have been in表示某人“已在某地停留一段时间,现仍在那里”,其后常带表示一段时间的状语。

  eg. ①The have been at the bus stp fr half an hur.他们在车站呆了半小时。(现在仍然在车站)

  ②We have been in Xi’an fr tw wees.

  我们在西安呆了两个多星期。(现仍在西安)

  ③Hw lng have the been in China?

  他们在中国呆了多长时间了?(仍在中国)

  (八)如何通过与一般过去时做比较,进一步掌握现在完成时?

  一般过去时和现在完成时的动作都发生在过去,但意义却不同.

  如: I learned ten English sngs(说明过去学过,现在是否记得,不是本句的内容)

  I have learnt ten English sngs.(learn发生在过去,但强调我现在懂英语歌曲)

  I cleaned the blacbard half an hur ag.(只说明“擦”和其发生的时间)

  I have cleaned the blacbard.(说明现在黑板是干净的)

  The teacher has written se new wrds n the blacbard(黑板上现在有单词)

  The teacher wrte se new wrds n the blacbard(黑板上现在没有单词)

  (2)一般过去时可以和表示过去的时间状语连用,如:esterda, last ear, three das ag, ust nw, 等。现在完成时不能和表示过去的时间状语连用,其时间状语可以是since…, fr…, ust, ever, never, befre, alread, et , s far, all ne’s life等

  (九)规则动词的过去分词和它的过去式相同,即在原形后加-ed(-d)。已学近80个不规则动词的过去分词约有半数也和它的过去式相同,现分类如下,以利于同学们记忆:

  1)原形中的元音字母有变化:

  get-gt-gt, sit –sat-sat win-wn-wn spit- spat- spat shine –shne- shne

  find- fund- fund hld-held-held eet- et-et stand- std-std

  understand-understd-understd feed- fed-fed hang-hung-hung

  2)原形中的辅音字母有变化:

  ae-ade-ade spill-spilt-spilt have/ has-had-had build-built-built

  send-sent-sent lend- lent- lent spend-spent-spent

  3)在原形后加t或d:

  spil-spilt-spilt learn-learnt-learnt ean-eant-eant hear-heard-heard

  pa-paid-paid sa-said-said lse-lst-lst la-laid-laid

  4)原形中的元音字母和辅音字母都有变化:

  feel-felt-felt sell-selt-selt spell-spelt –spelt eep-ept-ept

  sleep-slept-slept sweep-swept-swept leave-left-left sell-sld-sld

  tell-tld-tld catch-caught-caught teach-taught-taught bu-bught-bught

  bring-brught-brught thin-thught-thught wear-wre-wrn

  5)与原形相同:

  hit-hit-hit hurt-hurt-hurt let-let-let put-put-put read-read-read

  set-set-set shut-shut shut cst-cst-cst cut-cut-cut

  还有些不规则动词的过去分词与过去式不相同,为便于记忆,也分类如下:

  1)原形中的元音字母有变化:

  ring-rang-rung sing-sang-sung drin-dran-drun swi-swa-swu

  begin-began-begun sin-san-sun

  2)在原形上加-en:

  eat-ate-eaten fall-fell-fallen ride-rde-ridden write-wrte- written

  be-was/were-been rise-rse-risen frget-frgt-frgtten

  3:在原形上加-n:

  see-saw-seen give-gave-given drive-drve-driven tae-t-taen

  istae-ist-istaen draw-drew-drawn blw-blew-blwn

  grw-grew-grwn nw-new-nwn shw-shwed-shwn thrw-threw-thrwn

  4)在过去式上加-n:

  steal-stle-stlen brea-bre–bren chse-chse-chsen spea-spe-spen wae-we-wen

  5)与原形相同:ce-cae-ce run-ran-run bece-becae-bece

  6)原形、过去式和过去分词都不相同的:

  d-did-dne g-went-gne fl-flew-flwn lie-la-lain

  7)个别动词有两个过去式和过去分词,一个为规则变化,另一个为不规则变化:

  【典型例题】

  1. I have alread ______ the agazine fr 2 wees. I ust return it t the librar tda.

  A. lent B. bught C. brrwed D. ept

  解析:答案选D。

  这是一句现在完成时的句子,表示从过去开始持续到现在的行为,fr 表示一段时间,后接时间长度,本句的意思应为:这本杂志我已经借了两个星期了。在这样的时间状语为“fr+时间长度”的句子里,谓语动词要有可持续性,而不能为短暂性动词,因此,本题只能选D。因为“lent”,“bught”,“brrwed”均为短暂性动词,且“bught”,“lent”与句义不符。故选D。

  下面列出一些短暂性动词的持续性表达:

  arrive—be in brrw—eep bu—have fall ill—be ill

  in—be in leave—be awa fr begin—be n die—be dead等等

  2. —Where are the children? — The ________ t Beiing.

  A. have been B. have gne C. have left D. have arrived

  解析:答案选B。

  本题首先可排除C,D选项。“离开此地去北京”为“leave fr Beiing”,“到达北京”为“arrive in Beiing”. 然后再看A,B 选项,“have been t”意思是“去过某地”,表示曾经去过某地,现在已经回来或到其他地方,目前人已不在那里。“have gne t”意思是“去了某地”,表示人正去那里或已在去那里的途中。本题中,孩子们不在说话人所在的地方,所以应该选择B,表示他们已经去了北京或在去北京的途中。故选B。

  3. — _______ has he taught English in this schl? —Fr 2 ears.

  A. Hw lng B. When C. Hw sn D. Hw ften

  解析:答案选A。

  “Hw lng”问的是“一段时间”,这句话的意思是,他在这所学校教英语多久了,回答为“两年了。”“Hw lng”可与现在完成时一起用。“When”问的是一个时间点,可以和将来时、过去时连用,有时也可以和进行时放在一起用,但“When”不能和完成时一起使用。“Hw sn”意思是“多久以后”,用在将来时前面,而“Hw ften”问的是一个频率,可解释为“多久一次”,回答多为“Once a wee.”“Twice a nth”等等。故选A。

  4. —D u still write t ur friends these das?

  N. But I used ______ that when I was at schl.

  A. d B. did C. t ding D. t d

  解析:答案选D。

  本题涉及到“used”的几个不同用法,“be used t ding sth.”表示“习惯于做某事”,“used t d sth.”表示“过去常常做某事”,而“be used t d sth.”则表示“被用来做某事”,主语多为“sth.”.本题“used”前面没有be动词,再加上说的是过去我在学校里的事情,所以采用“used t d sth.”这个词组,整句话的意思就是,当我在学校里的时候,我常常那么做。故选D。

  5. She was ver _____________ at the _________ news.

  A. surprised; surprising B. surprised; surprised

  C. surprising; surprised D. surprising; surprising

  解析:答案选A。

  “be surprised at sth.”表示“对……感到惊奇”,主语是“sebd”,

  “surprising”表示“令人惊奇的”,主语多为 “sething”, 句子的意思是,她对“这个令人惊奇的消息感到很惊奇”。与此相类似的词语还有一些,如“exciting令人激动的”,“excited感到激动”,又如“interesting 有趣的”,“interested 感兴趣的”等等。故选A。

  6. He has never _______ a pen befre.

  A. lse B. t lse C. lst D. lsing

  解析:答案为C。 本题主要考查现在完成时态对谓语动词的要求。现在完成时态谓语动词的结构是have (has)+ 过去分词。本题空白处需要填过去分词,这样的话,那A、B、D就都不对了。

  7. 误:The twins have nt gt he alread.

  正:The twins have nt gt he et.

  解析:本题主要考查et 与 alread的用法区别,两个词都是副词,常与完成时态连用。et 用于否定句和疑问句,通常置于句尾;alread 常用于肯定句,当用于疑问句时,表示惊讶或希望得到肯定的答复,不用于否定句中,它可以在主要动词之前,也可置于句末。

  8. Ti has been at the factr_________ tw ears ag.

  A. fr B. since C. befre D. after

  解析:答案为B。 本题主要考查时间状语与谓语的关系。fr后跟时间段表示一段时间,since 后跟时间的起点,表示一段时间,befre 表示在什么时间之前,after则表示在什么时间之后。本句是完成时态,指自两年前以来如何,且两年前是个时间的(起)点,因此,此处应用since.

  9. 误:I saw the fil twice alread.

  正:I’ve seen the fil twice alread.

  解析:本题主要是一般过去时态与现在完成时态的概念错误。这电影我已看过两遍,说明我现在对电影内容很了解,故要用现在完成时态。

  10. —______u _____ ur watch?

  — N, ______.

  A. Did, find ut, I didn’t B. Have, fund, nt et

  C. Have, led fr, I haven’t D. Did, find, nt et

  答案:选“B”。全句应用现在完成时,强调到现在为止的情况“是否找到了手表”,答语:Nt et 相当于说 I haven’t fund it et.

  11. I have never seen the fil ______.

  A. ag B. ust nw C. befre D. later

  答案:选“C”。动词时态为现在完成时,与之搭配的词必须是ever, never, alread, et, befre, recentl 等词。而 ag, ust nw 等只能用于一般过去时的句子中,用later意思不通。

  12. Aunt Li _________ her he twn fr a lng tie.

  A. has left B. left C. has gne t D. has been awa fr

  答案:选“D”。与 fr a lng tie搭配的动词应该表示延续性,g, leave是短暂动词,故不能选。

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