初中英语知识点(初中化学知识点)( 三 ) _小常识

英语的时态（tense）是一种动词形式，不同的时态用以表示不同的时间与方式。下面就英语中常见的八种基本时态进行阐述，其它的时态都是在这八种时态的基础上结合而成的。一、一般现在时：1.概念：经常、反复发生的动作或行为及现在的某种状况。2.时间状语： always, usually, often, sometimes, every week (day, year, month…), once a week, on Sundays,3.基本结构：动词原形（如主语为第三人称单数，动词上要加（e）S）4.否定形式：am/is/are+not;此时态的谓语动词若为行为动词，则在其前加don"t,如主语为第三人称单数，则用doesn"t，同时还原行为动词。5.一般疑问句：把be动词放于句首；用助动词do提问，如主语为第三人称单数，则用does，同时，还原行为动词。6.例句：. It seldom snows here.He is always ready to help others.Action speaks louder than words.二、一般过去时：1.概念：过去某个时间里发生的动作或状态；过去习惯性、经常性的动作、行为。2.时间状语：ago, yesterday, the day before yesterday, last week(year, night, month…), in 1989, just now, at the age of 5, one day, long long ago, once upon a time, etc.3.基本结构：be动词；行为动词4.否定形式：was/were+not;在行为动词前加didn"t，同时还原行为动词。5.一般疑问句：was或were放于句首；用助动词do的过去式did 提问，同时还原行为动词。6.例句：She often came to help us in those days.I didn"t know you were so busy.三、现在进行时：1.概念：表示现阶段或说话时正在进行的动作及行为。2.时间状语：now, at this time, these days, etc.3.基本结构：am/is/are+doing4.否定形式：am/is/are+not+doing.5.一般疑问句：把be动词放于句首。6.例句： How are you feeling today?He is doing well in his lessons.四、过去进行时：1.概念：表示过去某段时间或某一时刻正在发生或进行的行为或动作。2.时间状语：at this time yesterday, at that time或以when引导的谓语动词是一般过去时的时间状语等。3.基本结构：was/were+doing4.否定形式：was/were + not + doing.5.一般疑问句：把was或were放于句首。6.例句：At that time she was working in a PLA unit.When he came in, I was reading a newspaper.五、现在完成时：1.概念：过去发生或已经完成的动作对现在造成的影响或结果，或从过去已经开始，持续到现在的动作或状态。2.时间状语：recently, lately, since…for…,in the past few years, etc.3.基本结构：have/has + done4.否定形式：have/has + not +d one.5.一般疑问句：have或has 。6.例句：I"ve written an article.It has been raining these days.六、过去完成时：1.概念：以过去某个时间为标准，在此以前发生的动作或行为，或在过去某动作之前完成的行为，即“过去的过去” 。2.时间状语：before, by the end of last year(term, month…),etc.3.基本结构：had + done.4.否定形式：had + not + done.5.一般疑问句：had放于句首。6.例句：As soon as we got to the station, the train had left.By the end of last month. We had reviewed four books七、一般将来时：1.概念：表示将要发生的动作或存在的状态及打算、计划或准备做某事。2.时间状语：tomorrow, next day(week, month, year…),soon, in a few minutes, by…,the day after tomorrow, etc.3.基本结构：am/is/are/going to + do；will/shall + do.4.否定形式：was/were + not; 在行为动词前加didn"t，同时还原行为动词。5.一般疑问句：be放于句首；will/shall提到句首。6.例句：They are going to have a competition with us in studies.It is going to rain.八、过去将来时：1.概念：立足于过去某一时刻，从过去看将来，常用于宾语从句中。2.时间状语：the next day(morning, year…),the following month(week…),etc.3.基本结构：was/were/going to + do；would/should + do.4.否定形式：was/were/not + going to + do;would/should + not + do.5.一般疑问句：was或were放于句首；would/should 提到句首。6.例句：He said he would go to Beijing the next day.I asked who was going there 柒·小寒^^2008-01-10 02:40 检举初中英语语法总结~~~
1. 动词的时态1.1 一般现在时的用法1）经常性或习惯性的动作，常与表示频腮度的时间状语连用。时间状语： every…, sometimes, at…, on Sunday 。2）客观真理，客观存在，科学事实。3）表示格言或警句。4）现在时刻的状态、能力、性格、个性比较：Now I put the sugar in the cup. 把糖放入杯子。I am doing my homework now. 我正在做功课。之一句用一般现在时，用于操作演示或指导说明的示范性动作，表示言行的瞬间动作。第二句中的now是进行时的标志，表示正在进行的动作的客观状况，所以后句用一般现在时。1.2 一般过去时的用法1）在确定的过去时间里所发生的动作或存在的状态。例如：时间状语有：yesterday, last week, an hour ago, the other day, in 1982等。例如：2）表示在过去一段时间内，经常性或习惯性的动作。例如：3）句型：It is time for . to do sth "到……时间了" "该……了" 。例如：It is time for you to go to bed. 你该睡觉了。It is time that . did sth. "时间已迟了" "早该……了"，例如It is time you went to bed. 你早该睡觉了。would （had） rather . did sth. 表示"宁愿某人做某事" 。例如：I"d rather you came tomorrow.还是明天来吧。4） wish, wonder, think, hope 等用过去时，作试探性的询问、请求、建议等，而一般过去时表示的动作或状态都已成为过去，现已不复存在。例如：I thought you might have some. 我以为你想要一些。比较：Christine was an invalid all her life.（含义：她已不在人间。）Christine has been an invalid all her life.（含义：她现在还活着）注意：用过去时表示现在，表示委婉语气。1）动词want, hope, wonder, think, intend 等。2）情态动词 could, would1.3 used to / be used toused to + do："过去常常"表示过去习惯性的动作或状态，但如今已不存在。be used to + doing：对……已感到习惯，或"习惯于"，to是介词，后需加名词或动名词。1.4 一般将来时1） shall用于之一人称，常被will 所代替。will 在陈述句中用于各人称，在征求意见时常用于第二人称。2） be going to +不定式，表示将来。a. 主语的意图，即将做某事。例如：What are you going to do tomorrow? 明天打算作什么呢？b. 计划，安排要发生的事。例如：The play is going to be produced next month 。这出戏下月开播。c. 有迹象要发生的事。例如：Look at the dark clouds, there is going to be a storm. 看那乌云，快要下雨了。3） be +不定式表将来，按计划或正式安排将发生的事。4） be about to +不定式，意为马上做某事。注意：be about to do 不能与tomorrow, next week 等表示明确将来时的时间状语连用。1.5 be going to / will 用于条件句时，be going to表将来,will表意愿。1.6 be to和be going tobe to 表示客观安排或受人指示而做某事，be going to 表示主观的打算或计划。例如：I am to play football tomorrow afternoon. 明天下午我去踢球。（客观安排）I"m going to play football tomorrow afternoon. 明天下午我想去踢球。（主观安排）1.7 一般现在时表将来1）下列动词come, go, arrive, leave, start, begin, return的一般现在时可以表示将来，主要用来表示在时间上已确定或安排好的事情。例如：The train leaves at six tomorrow morning. 火车明天上午六点开。When does the bus star? It stars in ten minutes. 汽车什么时候开？十分钟后。2）以here, there等开始的倒装句，表示动作正在进行。例如：Here comes the bus. = The bus is coming. 车来了。There goes the bell. = The bell is ringing. 铃响了。3）在时间或条件句中。例如：When Bill comes （不是will come）, ask him to wait for me. 比尔来后，让他等我。I"ll write to you as soon as I arrive there. 我到了那里，就写信给你。4）在动词hope, take care that, make sure that等的宾语从句中。例如：I hope they have a nice time next week. 我希望他们下星期玩得开心。Make sure that the windows are closed before you leave the room. 离开房间前，务必把窗户关了。1.8 用现在进行时表示将来下列动词come, go, arrive, leave, start, begin, return等现在进行时可以表示将来。例如：I"m leaving tomorrow. 明天我要走了。Are you staying here till next week? 你会在这儿呆到下周吗？11.9 现在完成时现在完成时用来表示之前已发生或完成的动作或状态，其结果的影响现在还存在；也可表示持续到现在的动作或状态。其构成：have （has） +过去分词。1.10 比较一般过去时与现在完成时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。2）一般过去时常与具体的时间状语连用，而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, in1980, in October, just now等，皆为具体的时间状语。现在完成时的时间状语：for, since, so far, ever, never, just, yet, till/until, up to now, in past years, always等，皆不确定的时间状语。共同的时间状语：this morning, tonight, this April, now, already, recently, lately 等。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. 。一般过去时常用的非持续性动词有come, go, leave, start, die, finish, become, get married等。例如：I saw this film yesterday. （强调看的动作发生过了）I have seen this film. （强调对现在的影响，电影的内容已经知道了）Why did you get up so early? （强调起床的动作已发生过了）Who hasn"t handed in his paper? （强调有卷子未交，疑为不公平竞争）He has been in the League for three years. （在团内的状态可延续）He has been a League member for three years. （是团员的状态可持续）句子中如有过去时的时间副词（如yesterday, last, week, in 1960）时，不能使用现在完成时，要用过去时。（错）Tom has written a letter to his parents last night.（对）Tom wrote a letter to his parents last night.1.11 用于现在完成时的句型1）It is the first / second time.... that…结构中的从句部分，用现在完成时。例如：It is the first time that I have visited the city. 这是我之一次访问这城市。This is the first time （that） I"ve heard him sing. 这是我之一次听他唱歌。注意：It was the third time that the boy had been late.2）This is +形容词更高级+that…结构，that 从句要用现在完成时。例如：This is the best film that I"ve （ever） seen. 这是我看过的更好的电影。注意：非延续性动词的否定形式可以与表示延续时间的状语连用。即动作不发生的状态是可以持续的。（错）I have received his letter for a month.（对）I haven"t received his letter for almost a month.1.12 比较since和forSince 用来说明动作起始时间，for用来说明动作延续时间长度。例如：I have lived here for more than twenty years.我住在这儿二十多年了。I have lived here since I was born. 我从出生起就住在这儿了。注意：并非有for 作为时间状语的句子都用现在完成时。I worked here for more than twenty years. （我现在已不在这里工作。）I have worked here for many years.（现在我仍在这里工作。）注意：用句型转换的，很容易排除非延续动词在有for/since结构的完成时中的误用。1）（对） Tom has studied Russian for three years. = Tom began to study Russian three years ago, and is still studying it now.2）（错） Harry has got married for six years. = Harry began to get married six years ago, and is still getting married now.显然，第二句不对，它应改为 Harry got married six years ago. 或 Harry has been married for six years.1.13 since的四种用法1） since +过去一个时间点（如具体的年、月、日期、钟点、1980, last month, half past six）。例如：I have been here since 1989. 1989起，我一直在这儿。2） since +一段时间+ ago 。例如：I have been here since five months ago. 我在这儿，已经有五个月了。3） since +从句。例如：Great changes have taken place since you left. 你走后，变化可大了。Great changes have taken place since we were here. 我们走后，变化可大了。4） It is +一段时间+ since从句。例如：It is two years since I became a postgraduate student. 我考上研究生有两年了。1.14 延续动词与瞬间动词1）用于完成时的区别延续动词表示经验、经历；瞬间动词表示行为的结果，不能与表示段的时间状语连用。例如：He has completed the work. 他已完成了那项工作。（表结果）I"ve known him since then. 我从那时起就认识他了。（表经历）2）用于till / until从句的差异延续动词用于肯定句，表示"做……直到……" 瞬间动词用于否定句，表示"到……，才……" 。例如：He didn"t come back until ten o"clock. 他到10 点才回来。He slept until ten o"clock. 他一直睡到10点。1.15 过去完成时1）概念：表示过去的过去---|----------|--------|----> 其构成是had +过去分词构成。那时以前那时现在2）用法a. 在told, said, knew, heard, thought等动词后的宾语从句。例如：She said （that）she had never been to Paris. 她告诉我她曾去过巴黎。b. 状语从句在过去不同时间发生的两个动作中，发生在先，用过去完成时；发生在后，用一般过去时。例如：When the police arrived, the thieves had run away. 警察到达时，小偷们早就跑了。c. 表示意向的动词，如hope, wish, expect, think, intend, mean, suppose等，用过去完成时表示"原本…，未能…" 。例如：We had hoped that you would come, but you didn"t. 那时我们希望你能来，但是你没有来。3）过去完成时的时间状语before, by, until , when, after, once, as soon as 。例如：He said that he had learned some English before. 他说过他以前学过一些英语。By the time he was twelve, Edison had began to make a living by himself. 到了十二岁那年，爱迪生开始自己谋生。Tom was disappointed that most of the guests had left when he arrived at the party.汤姆失望了，因为他到达晚会时，大部分客人已经走了。注意： had hardly… when 还没等…… 就…… 。例如：I had hardly opened the door when I he hit me. 我刚打开门，他就打了我。had no sooner…than 刚…… 就…… 。例如：He had no sooner bought the car than he sold it. 他刚买了这辆车，转眼又卖了。1.16 用一般过去时代替过去完成时1）两个动作如按顺序发生，又不强调先后，或用then，and，but 等连词时，多用一般过去时。例如：When she saw the mouse，she screamed. 她看到老鼠，就叫了起来。My aunt gave me a hat and I lost it. 姑妈给了我一顶帽子，我把它丢了。2 ）两个动作相继发生，可用一般过去时；如之一个动作需要若干时间完成，用过去完成时。例如：When I heard the news, I was very excited.3）叙述历史事实，可不用过去完成时，而只用一般过去时。例如：Our teacher told us that Columbus discovered America in 1492.1.17 将来完成时1）构成will have done2）概念a. 状态完成：表示某事继续到将来某一时为止一直有的状态。例如：They will have been married for 20 years by then. 到那时他们结婚将有二十年了。b. 动作完成：表示将来某一时或另一个将来的动作之前，已经完成的动作或获得的经验。例如：You will have reached Shanghai by this time tomorrow. 明天此时，你已经到达上海了。1.18 现在进行时现在进行时的基本用法：a. 表示现在（指说话人说话时）正在发生的事情。例如：We are waiting for you. 我们正在等你。b. 习惯进行：表示长期的或重复性的动作，说话时动作未必正在进行。例如：Mr. Green is writing another novel. 他在写另一部小说。（说话时并未在写，只处于写作的状态。）c. 表示渐变，这样的动词有：get, grow, become, turn, run, go, begin等。例如：The leaves are turning red. 叶子在变红。It"s getting warmer and warmer. 天越来越热了。d. 与always, constantly, forever 等词连用，表示反复发生的动作或持续存在的状态，往往带有说话人的主观色彩。例如：You are always changing your mind. 你老是改变主意。1.19 不用进行时的动词1）表示事实状态的动词，如have, belong, possess, cost, owe, exist, include, contain, matter, weigh, measure, continue等。例如：I have two brothers. 我有两兄弟。This house belongs to my sister. 这房子是我姐的。2）表示心理状态的动词，如know, realize, think see, believe, suppose, imagine, agree, recognize, remember, want, need, forget, prefer, mean, understand, love, hate等。例如：I need your help. 我需要你的帮助。He loves her very much. 他爱她很深。3）瞬间动词，如accept, receive, complete, finish, give, allow, decide, refuse等。例如：I accept your advice. 我接受你的劝告。4）系动词，如seem, remain, lie, see, hear, ell, feel, taste, get, become, turn等。例如：You seem a little tired. 你看上去有点累。1.20 过去进行时1）概念：表示过去某时正在进行的状态或动作。2）过去进行时的主要用法是描述一件事发生的背景；一个长动作延续的时候，另一个短动作发生。3）常用的时间状语有this morning, the whole morning, all day yesterday, from nine to ten last evening, when, while等。例如：My brother fell while he was riding his bicycle and hurt himself. 我兄弟骑车时摔了下来，受了伤。It was raining when they left the station. 他们离开车站时，正下着雨。When I got to the top of the mountain, the sun was shining. 我到达山顶时，阳光灿烂。