人教版英语八年级下册 Unit8 现在完成时专题讲解 (无答案)
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授课主题 现在完成时1
教学目的 通过对本节知识点的学习使学生:
1.理解并熟练动词完成时态,并正确运用实践。
2.掌握完成时态在中考中的考点详情
3..灵活运用动词时态
重、难点 动词过去分词规则变化与不规则变化的掌握
教学内容
课程导入
知识讲解
现在完成时
含义: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
构成:
1. 肯定句:have(has)+过去分词
注意:该句式中的have 或has是助动词,has用于第三人称单数,其它人称一律用have。
2. 否定句:haven’t(hasn’t)+过去分词
3. 疑问句:助动词have或has提到主语之前。
回答用Yes, …have(has).
No, …haven’t(hasn’t). 2 / 7
动词过去分词规则变化与不规则变化
(一) 规则变化:与动词过去式规则相同。
1. 一般直接在词尾加上ed。look — looked
2. 以e结尾的动词,直接加d。move — moved
3. 以y结尾,y前面是辅音字母的动词,变y 为i,再加ed。carry — carried
4. 部分动词需双写尾字母,加ed。stop — stopped
(二)不规则变化
不规则动词的变化因词而异。
AAB型:beat-beat-beaten 打败
ABC 型 be-was/were-been
begin-began-begun
AAA型 cost-cost-cost
hit-hit-hit
ABA型 become-became-become
ABB型 burn-burnt-burnt
现在完成时的用法
(1)表示结果的现在完成时
现在完成时着眼于过去的动作对现在产生的结果或影响。
I have bought a pen.我买了一支笔。(结果:I have a pen now.)
The temperature has increased by 10℃.温度上升了10摄氏度。(结果:It is quite hot now.)
【注意】现在完成时的上下文所指的时态必须呼应。
(误)I have bought a pen but I have lost it now.(have bought
表示你现在已经有笔了,这和后面的have lost有矛盾)
(正)I bought a pen but I have lost it now.我(过去)买了一支笔,但我已经把它丢了。
(误)I have lost my pen but I have found it now.(have lost
强调你现在已经没有笔了,与后面have found的意思有冲突)
(正)I lost my pen but I have found it now.我丢了一支笔,但现在已经找到了。
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(2)表示经历的现在完成时
强调过去某一时刻到说话时这段时间中的经历。
Have you ever been to the Great Wall?你去过长城吗?
(3)表示延续的现在完成时
表示一个动作或状态从过去某时开始,持续到现在,可能要继续下去。
He's loved fishing for a long time.他爱好钓鱼为时已久。(他现在仍爱好钓鱼)
【注意】现在完成时的“未完成”用法既可用于动态动词(主要是持续动词),
也可用于状态动词,
但一般不用于表短暂动作或位置转移的动词,如:open, break, go, come, arrive, leave如用这类动词表示“未完成”,通常只限于否定结构。
I haven't seen a film for weeks.
我已经好几个星期没看电影了。
3、现在完成时的时间状语
(1)与现在完成时“已完成”用法连用的时间状语
①不确定的过去时间状语:already, yet, before, recently, lately等
I've seen the film before.我以前看过这部电影。
②频度时间状语:often, sometimes, ever, never, once, rarely等
We have never heard of that.我们从未听说过这事。
③包含现在时间在内的时间状语:now, just, today, this morning, this week, this year等
I have just finished the letter now.我现在刚写完信。
【比较】already和yet用法上的区别
already常用于肯定句,置于句中,有时也可用在疑问句中暗示惊讶的心情。
yet常用于否定句和疑问句,置于句末。
She has already gone.她早就走了。 4 / 7
⑵ in the past/last few years(过去几年来)
so far=up to now/till now/by now these days
since /ever since+过去时间点
for+时间段
注意:
①since+一段时间+ago=for+时间段;
since two weeks ago=for two weeks;
I have kept the library book for a week.=I have kept the library book since a week ago.
②since+时间点=for+时间段
since 2000=for 8 years
③since+从句(常用一般过去时)
The Greens have lived in Beijing since they moved to Beijing from Paris.
④have got, has got 虽然是现在完成时, 但have got=have; has got=has
I have a new bike.=I have got a new bike
巩固练习
1. I’m sorry you the wonderful football game. It was just over.
A. have lost B. have missed C. are missing D. will lose
2. —You seem to know much about the city.
—That’s true. I it three times.
A. visited B. had visited C. have visited D. will visit
3. —Would you like to visit Shantou City with me this summer vacation?
—No, thanks. I it before. Besides, it’s hot and humid there in summer.
A. have visited B. visited C. will visit
4. It is said the Chery(奇瑞) a new kind of car recently.
A. has developed B. developed C. develops D. had developed
5. —Bad luck! It’s too late!
—It doesn’t matter. The movie for only a few minutes. You can’t miss it. 5 / 7
A. has begun B. has been on C. began D. was on
6.. —You have my dictionary for two weeks.
—Sorry, I’ll give it back to you right now.
A. lent B. borrowed C. kept
现在完成时与一般过去时的比较
1) 一般过去时表示过去某时发生的动作或单纯叙述过去的事情,强调动作;
现在完成时为过去发生的,强调过去的事情对现在的影响,强调的是影响。
I saw this film yesterday. 我昨天看了这部电影。(强调看的动作发生过了。)
I have seen this film. 我看过这部电影了。(强调对现在的影响,电影的内容已经知道了。)
2) 一般过去时常与具体的表示过去的时间状语连用;
现在完成时通常与模糊的时间状语连用,或无时间状语。
一般过去时的时间状语: yesterday; last week;…ago; in1990; in October; just now …
现在完成时的时间状语: already; ever; for; just; never; since; yet;so far; till/until;
up to now;in the past few years; recently…
3) 现在完成时可表示持续到现在的动作或状态,动词一般是延续性的,如:live;teach;learn;
work;study;know等;
一般过去时常用的非持续性动词有come, go, leave, start, die, finish, become等。
She joined the League three years ago. 她三年前入团了。(加入的动作不是延续的)
She has been in the League for three years (since three years ago).
她入团三年了。(在团内状态可延续)
She has been a League member for three years (since three years ago).
她入团三年了。(是团员的状态,可持续)
非延续性动词和延续性动词的转换