人教版英语八年级上册第二单元语法知识

1、一.频度副词1 .频度副词的位置频度副词常放在be动词、助动词、情态动词之后，实义动词之前。如:He is often late for school.他经常上学迟到。I shall always remember my first day at school.我将永远记得我上学的第一天。I usually do some shopping with my parents on Sundays.我经常在星期天和我的父母一起去买东西。2 .常见的频率副词频度副词，通常放在行为动词之前，系动词be、助动词和情态动词之后。它们 所表示的含义和频度各不相同。下面是常见的频率副词always总是usua

2、lly通常地；一般地often时常；常常sometimes有时hardly ever几乎不never从不 always的频度为100%,表示动作重复、状态继续，中间没有间断，意为“总是”。例： The sun always rises in the east.太阳总是在东边升起。 usually的频度为70%左右，意为“通常，平常”，较少例外。例：He usually goes to bed at ten oclock.他通常在十点钟上床睡觉。 often的频度为50%左右，意为“时常，经常”，不如usually那么频繁，表示动 作重复，中间有间断。very often语气比often重，常位

3、于句首或句末。例：He is often late for school.他经常上学迟到。He doesn't go home very often.他不经常回家。 sometimes的频度为20%左右，意为“有时”，表示动作偶尔发生。（列：It is sometimes hot and sometimes cold.天气有时热有时冷。 never的频度为0,意为“从来不,永不例： My parents are never late for work.我的父母上班从不迟到。 hardly可作副词，意为“几乎不，几乎没有”。如： Words can hardly describe how

4、 excited we were. 我们激动的心情难以形容。 seldom可作副词,意、为“很少，不常”。如:I seldom have lunch at home.我很少在家吃午饭。It seldom snows there.那里冬天很少下雪。3.频率副词的提问对时间频率，如once a year, twice a week等提问，疑问词用How ofteno how often指每隔多久，主要用来对频率进行提问。如：-How often do you go to see a film?你多久去看一次电影？-I hardly ever go to see a film.我几乎从不看电影。例子

5、I go to school five times a week,一How often do you go to school?Students have vacations twice a year.>How often do students have vacations? The Smiths go travelling every other year.>How often do the Smiths go travelling?注意：对具体次数，如once, twice, three times等提问，疑问词用How many timesI go to school fi

6、ve times a week.>How many times do you go to school in a week?Students have vacations twice a yeai.一How many times do students have vacations in a year?4.精确的频度副词，即用次数表达事情发生的频率中文表达央文表达例子一次onceonce a week两次twicetwice a month三次或以上基数词+timesthree times a day例： We go to school five times a week.我们一周去学校

7、五次。The magazine comes out once a month. 这杂志一个月出版一次。二.一般现在时L定义：一般现在时表示经常性、习惯性、重复性发生的动作或存在的状态。一 般现在时常常和频度副词always, usually, often, sometimes, never等连用。2.动词形态：一般现在时的动词有动词原形和动词第三人称单数形式（简称三 单）。当主语为第三人称单数时，谓语动词也相应用三单形式。动词三单的变化 规则如下表：分类规则例词一般情况卜加swalk-walks以sh,ch结尾jJD-esguess-guesses fix-fixes brush-brushe

8、s watch-watches以“辅音字母+y"结尾变 y 为 i to-esstudy-studies以。结尾加-esgo-goes3 ,句型结构：a.当动词为be动词时句型例可肯定句主语+am/is/are+其他.Tom is clever.否定句主语+am/is/are+not+其他.（is和not的缩写形式为isn't； are和not缩写形式为aren't）Tom isn't clever.一般疑问句 和简略回答Am/I s/Am+主语+其他？ Yes.主语+am/is/are. No.主谡+an¥is/are+not.-Is Tom cl

9、ever?-Yes. he is.-No, he isn t.特殊疑问句特殊疑问词+am/is/are+（主语）+其他？Why is Tom clever?Who is clever?b .当动词为实义动词时:句型结构例句肯定句主语+动词原形/动词三单+其他.Tom works hard.否定句主 语+do/does+not+动 词 原形+ 其他.（do和not缩写形式为 don't; does和 not白勺缩写形式为 doesn't）1 don't like playing basketball.Tom doesn't work hard.般疑问句Do/Doe

10、s+主话+动词厚形+其 他？Does Tom work hard?特殊疑问句特殊疑问词+do/doe6+主语+动 词原形+其他？Who+动词三单+其他？How does Tom work?Who works hard?4. 一般现在时的主要用法:表示经常发生的动作、存在的状态或日常习惯，常与everyday, often, always, sometimes等时间状语连用。She gets up at six every day.她每天六点起床。表示主语的特征、性格、能力等。Tom studies very hard.Tom学习非常努力。表示客观事实或普遍真理。The sun rises in the east and sets in the west.太阳从东边升起西边落下。Actions speak louder than words.行动胜于言辞。 新闻标题或小说章节的题目。Bank Robbery: Robbers take SI, 000, 000.银行抢劫案：匪徒抢走一白万美元。三.由连词although引导的让步状语从句 although意为“虽然，然而，尽管"，是连词，引导让步状语从句，大部分情况 下