常用英语语法（合集6篇）由网友“陈小猫在流浪”投稿提供，以下是小编给大家整理的常用英语语法，欢迎大家前来参阅。
篇1：英语语法
1.1 名词复数的规则变化
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情况 构成方法 读音 例词
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一般情况 加 -s 1.清辅音后读/s/; map-maps
2.浊辅音和元音后 bag-bags
读 /z/; car-cars
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以s,sh,ch,
x等结尾的词 加 -es 读 /iz/ bus-buses
watch-watches
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以ce,se,ze,
(d)ge等结尾
的词加 -s 读 /iz/ license-licenses
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以辅音字母+y 变y 为i
结尾的词 再加es 读 /z/ baby---babies
___________________________________________________1.2 其它名词复数的规则变化
1) 以y结尾的专有名词，或元音字母+y 结尾的名词变复数时，直接加s变复数：
如： two marys the henrys
monkey---monkeys holiday---holidays
比较： 层楼：storey ---storeys story---stories
2) 以o 结尾的名词，变复数时：
a. 加s，如： photo---photos piano---pianos
radio---radios zoo---zoos；
b. 加es，如：potato--potatoes tomato--tomatoes
c. 均可，如：zero---zeros / zeroes
3) 以f或fe 结尾的名词变复数时：
a. 加s，如： belief---beliefs roof---roofs
safe---safes gulf---gulfs；
b. 去f,fe 加ves，如：half---halves
knife---knives leaf---leaves wolf---wolves
wife---wives life---lives thief---thieves；
c. 均可,如： handkerchief:
handkerchiefs / handkerchieves
1.3 名词复数的不规则变化
1）child---children foot---feet tooth---teeth
mouse---mice man---men woman---women
注意：与 man 和 woman构成的合成词，其复数形式也是 -men 和-women。
如： an englishman，two englishmen. 但german不是合成词，故复数形式为germans；bowman是姓，其复数是the bowmans。
2）单复同形 如：
deer，sheep，fish，chinese，japanese
li，jin，yuan，two li，three mu，four jin
但除人民币元、角、分外，美元、英镑、法郎等都有复数形式。如:
a dollar, two dollars; a meter, two meters
3）集体名词，以单数形式出现，但实为复数。
如： people police cattle 等本身就是复数，不能说 a people，a police，a cattle，但可以说
a person，a policeman，a head of cattle,the english，the british，the french，the chinese，the japanese，the swiss 等名词，表示国民总称时，作复数用。
如： the chinese are industries and brave. 中国人民是勤劳勇敢的。
4）以s结尾，仍为单数的名词，如：
a. maths，politics，physics等学科名词，为不可数名词，是单数。
b. news 是不可数名词。
c. the united states，the united nations 应视为单数。
the united nations was organized in 1945. 联合国是1945年组建起来的。
d. 以复数形式出现的书名，剧名，报纸，杂志名，也可视为单数。
“the arabian nights” is a very interesting story-book.
<<一千零一夜>>是一本非常有趣的故事书。
5) 表示由两部分构成的东西，如：glasses (眼镜) trousers, clothes
若表达具体数目，要借助数量词 pair(对，双); suit(套); a pair of glasses; two pairs of trousers
6） 另外还有一些名词，其复数形式有时可表示特别意思，如：goods货物，waters水域，fishes（各种）鱼
1.4 不可数名词量的表示
1）物质名词
a. 当物质名词转化为个体名词时。
比较： cake is a kind of food. 蛋糕是一种食物。 (不可数)
these cakes are sweet. 这些蛋糕很好吃。 (可数)
b. 当物质名词表示该物质的种类时，名词可数。
this factory produces steel. (不可数)
we need various steels. (可数)
c. 当物质名词表示份数时，可数。
our country is famous for tea.
我国因茶叶而闻名。
two teas, please.
请来两杯茶。
2） 抽象名词有时也可数。
four freedoms 四大自由
the four modernizations四个现代化
物质名词和抽象名词可以借助单位词表一定的数量。
如：
a glass of water 一杯水
a piece of advice 一条建议
1.5 定语名词的复数
名词作定语一般用单数，但也有以下例外。
1) 用复数作定语。
如：sports meeting 运动会
students reading-room 学生阅览室
talks table 谈判桌
the foreign languages department 外语系
2) man, woman, gentleman等作定语时，其单复数以所修饰的名词的单复数而定。
如：men workers women teachers
gentlemen officials
3) 有些原有s结尾的名词，作定语时，s保留。
如：goods train (货车)
arms produce 武器生产
customs papers 海关文件
clothes brush衣刷
4) 数词+名词作定语时，这个名词一般保留单数形式。
如：two-dozen eggs 两打/（二十四个鸡蛋)
a ten-mile walk 十里路
two-hundred trees 两百棵树
a five-year plan. 一个五年计划
个别的有用复数作定语的，如： a seven-years child
1.6 不同国家的人的单复数
名称 总称(谓语用复数） 一个人 两个人
中国人 the chinese a chinese two chinese
瑞士人 the swiss a swiss two swiss
澳大利亚人the an two
australians australian australians
俄国人 the russians a russian two russians
意大利人 the italians an italian two italians
希腊人 the greek a greek two greeks
法国人 the french a frenchman two
frenchmen
日本人 the japanese a japanese two japanese
美国人 the americans an american two americans
印度人 the indians an indian two indians
加拿大人 the canadians a canadian two canadians
德国人 the germans a germans two germans
英国人 the english an englishman two
englishmen
瑞典人 the swedish a swede two swedes1.7 名词的格
在英语中有些名词可以加“'s”来表示所有关系，带这种词尾的名词形式称为该名词的所有格，如：a teacher's book。名词所有格的规则如下：
1） 单数名词词尾加“'s”，复数名词词尾没有s，也要加“'s”，如the boy's bag 男孩的书包，men's room 男厕所。
2） 若名词已有复数词尾-s ，只加“'”，如：the workers' struggle 工人的斗争。
3） 凡不能加“'s”的名词，都可以用“名词+of +名词”的结构来表示所有关系，如：the title of the song 歌的名字。
4） 在表示店铺或教堂的名字或某人的家时，名词所有格的后面常常不出现它所修饰的名词，如：the barber's 理发店。
5） 如果两个名词并列，并且分别有's，则表示“分别有”；只有一个's，则表示'共有'。
如：john's and mary's room（两间） john and mary's room（一间）
6） 复合名词或短语，'s 加在最后一个词的词尾。
如：a month or two's absence
篇2：英语语法
5.1 系动词
系动词亦称联系动词（link verb），作为系动词，它本身有词义，但不能单独用作谓语，后边必须跟表语（亦称补语），构成系表结构说明主语的状况、性质、特征等情况。
说明：
有些系动词又是实义动词，该动词表达实义时，有词义，可单独作谓语，例如：
he fell ill yesterday.
他昨天病了。（fell是系动词，后跟补足语，说明主语情况。）
he fell off the ladder.
他从梯子上摔下来。fell是实义动词，单独作谓语。
1）状态系动词
用来表示主语状态，只有be一词，例如：
he is a teacher. 他是一名教师。（is与补足语一起说明主语的身份。）
2）持续系动词
用来表示主语继续或保持一种状况或态度，主要有keep, rest, remain, stay, lie, stand, 例如：
he always kept silent at meeting. 他开会时总保持沉默。
this matter rests a mystery. 此事仍是一个谜。
3）表像系动词
用来表示“看起来像”这一概念，主要有seem, appear, look, 例如：
he looks tired. 他看起来很累。
he seems (to be) very sad. 他看起来很伤心。
4）感官系动词
感官系动词主要有feel, smell, sound, taste, 例如：
this kind of cloth feels very soft.
这种布手感很软。
this flower smells very sweet.
这朵花闻起来很香。
5）变化系动词
这些系动词表示主语变成什么样，变化系动词主要有become, grow, turn, fall, get, go, come, run.
例如：
he became mad after that. 自那之后，他疯了。
she grew rich within a short time. 她没多长时间就富了。
6）终止系动词
表示主语已终止动作，主要有prove, trun out, 表达“证实”，“变成”之意，例如：
the rumor proved false. 这谣言证实有假。
the search proved difficult. 搜查证实很难。
his plan turned out a success. 他的计划终于成功了。（turn out表终止性结果）
5.2 什么是助动词
1）协助主要动词构成谓语动词词组的词叫助动词（auxiliary verb）。被协助的动词称作主要动词（main verb）。
助动词自身没有词义，不可单独使用，例如：
he doesn't like english. 他不喜欢英语。
（doesn't是助动词，无词义；like是主要动词，有词义)
2） 助动词协助主要动词完成以下功用，可以用来：
a. 表示时态，例如：
he is singing. 他在唱歌。
he has got married. 他已结婚。
b. 表示语态，例如：
he was sent to england. 他被派往英国。
c. 构成疑问句，例如：
do you like college life? 你喜欢大学生活吗？
did you study english before you came here? 你来这儿之前学过英语吗？
d. 与否定副词not合用，构成否定句，例如：
i don't like him. 我不喜欢他。
e. 加强语气，例如：
do come to the party tomorrow evening. 明天晚上一定来参加晚会。
he did know that. 他的确知道那件事。
3） 最常用的助动词有：be, have, do, shall, will, should, would
5.3 助动词be的用法
1） be +现在分词，构成进行时态，例如：
they are having a meeting. 他们正在开会。
english is becoming more and more important. 英语现在越来越重要。
2) be + 过去分词，构成被动语态，例如：
the window was broken by tom.. 窗户是汤姆打碎的。
english is taught throughout the world. 世界各地都教英语。
3） be + 动词不定式，可表示下列内容：
a. 表示最近、未来的计划或安排，例如：
he is to go to new york next week.. 他下周要去纽约。
we are to teach the freshpersons. 我们要教新生。
说明： 这种用法也可以说成是一种将来时态表达法。
b. 表示命令，例如：
you are to explain this. 对此你要做出解释。
he is to come to the office this afternoon. 要他今天下午来办公室。
c. 征求意见，例如：
how am i to answer him? 我该怎样答复他？
who is to go there? 谁该去那儿呢？
d. 表示相约、商定，例如：
we are to meet at the school gate at seven tomorrow morning. 我们明天早晨7点在校门口集合。
5.4 助动词have的用法
1）have +过去分词，构成完成时态，例如：
he has left for london. 他已去了伦敦。
by the end of last month, they had finished half of their work.
上月未为止，他们已经完成工作的一半。
2）have + been +现在分词，构成完成进行时，例如：
i have been studying english for ten years.
我一直在学英语，已达十年之久。
3）have+been +过去分词，构成完成式被动语态，例如：
english has been taught in china for many years.
中国教英语已经多年。
5.5 助动词do 的用法
1） 构成一般疑问句，例如：
do you want to pass the cet? 你想通过大学英语测试吗？
did you study german? 你们学过德语吗？
2） do + not 构成否定句，例如：
i do not want to be criticized. 我不想挨批评。
he doesn't like to study. 他不想学习。
in the past, many students did not know the importance of english. 过去，好多学生不知道英语的重要性。
3) 构成否定祈使句，例如：
don't go there. 不要去那里。
don't be so absent-minded. 不要这么心不在焉。
说明： 构成否定祈使句只用do，不用did和does。
4） 放在动词原形前，加强该动词的语气，例如：
do come to my birthday party. 一定来参加我的生日宴会。
i did go there. 我确实去那儿了。
i do miss you. 我确实想你。
5） 用于倒装句，例如：
never did i hear of such a thing. 我从未听说过这样的事情。
only when we begin our college life do we realize the importance of english.
只有在开始大学生活时我们才认识到英语的重要性。
说明： 引导此类倒装句的副词有never, seldom, rarely, little, only, so, well等。
6） 用作代动词，例如：
---- do you like beijing? --你喜欢北京吗？
---- yes, i do. --是的，喜欢。（do用作代动词，代替like beijing.）
he knows how to drive a car, doesn't he?
他知道如何开车，对吧？
5.6 助动词shall和will的用法
shall和will作为助动词可以与动词原形一起构成一般将来时，例如：
i shall study harder at english. 我将更加努力地学习英语。
he will go to shanghai. 他要去上海。
说明：
在过去的语法中，语法学家说shall用于第一人称，will 只用于第二、第三人称。现在，尤其是在口语中，will常用于第一人称，但shall只用于第一人称，如用于第二、第三人称，就失去助动词的意义，已变为情态动词，试比较:
he shall come. 他必须来。（shall有命令的意味。）
he will come. 他要来。（will只与动词原形构成一般将来时。）
5.7 助动词should,would的用法
1）should无词义，只是shall的过去形式，与动词原形构成过去将来时，只用于第一人称，例如：
i telephoned him yesterday to ask what i should do next week.
我昨天给他打电话，问他我下周干什么。
比较：
“what shall i do next week?” i asked.
“我下周干什么？”我问道。（可以说，shall变成间接引语时，变成了should。）
2） would也无词义，是will的过去形式，与动词原形构成过去将来时，用于第二、第三人称，例如：
he said he would come. 他说他要来。
比较：
“i will go,” he said. 他说：“我要去那儿。”
变成间接引语，就成了：
he said he would come.
原来的will变成would，go变成了come.。
5.7 助动词should,would的用法
1）should无词义，只是shall的过去形式，与动词原形构成过去将来时，只用于第一人称，例如：
i telephoned him yesterday to ask what i should do next week.
我昨天给他打电话，问他我下周干什么。
比较：
“what shall i do next week?” i asked.
“我下周干什么？”我问道。（可以说，shall变成间接引语时，变成了should。）
2） would也无词义，是will的过去形式，与动词原形构成过去将来时，用于第二、第三人称，例如：
he said he would come. 他说他要来。
比较：
“i will go,” he said. 他说：“我要去那儿。”
变成间接引语，就成了：
he said he would come.
原来的will变成would，go变成了come.。
5.9 非谓语动词
在句子中充当除谓语以外的句子成分的动词形式叫做非谓语动词。非谓语动词分为三种形式:不定式，动名词，和分词(分词包括现在分词和过去分词)。
1）不定式
时态语态 主动被动
一般式 to doto be done
完成式 to have done to have been done
2）动名词
时态语态 主动被动
一般式 doing being done
完成式 having done having been done
3）分词
时态语态 主动被动
一般式 doing being done
完成式 having done having been done
否定形式： not +不定式， not + 动名词， not + 现在分词
篇3：英语语法网
英语语法网：虚拟语气用在其它名词性从句中
1.虚拟语气用在 suggest, demand, insist, ask, move, advise. desire, order, propose, require, recommend, request, maintain, vote 等表示建议，命令，请求的动词后的宾语从句中，从句的谓语用 should + 原形动词，但美国英语中常要省去 should 。例如：
I suggest we start at once.
They propose that you (should) read the rules carefully.
The commander ordered that the soldier fire at the enemy.
He insisted that he go there on foot.
I move that the meeting be adjourned. 我提议休会. move:(在会议上)提议，动议
Example:
He insisted that we all ______ in his office at one o'clock.
a. be b. to be c. would be d. shall be
He asked that it ______ done right away.
a. is b. be c. shall be d. must be
He recommended that John ______ with him.
a. must go b. went c. will go d. go
2.虚拟语气用在 It is + 形容词(或过去分词)+ that... .的主语从句中，表示要求，建议，提议，命令，请求等，英国英语中从句的谓语用“should +原形动词(或完成式)构成”，而美国英语中则要求用原形动词。该句型中常用的形容词或过去分词有：advisable, desirable, essential, important, better, keen, natural, necessary, probable, possible, strange, vital, desired, demanded, requested, suggested, recommended, required 等。例如：
It is necessary that the machine (should) be oiled once a week.
It is important that everyone (should) obey the law.
It is suggested that you take a walk after supper.
Example:
It is necessary that he ______ in time to attend the meeting.
a. come b. came c. would come d. need come
It was proposed that the matter ______ discussed at the next meeting.
a. would be c. will be c. was d. be
It is strange that she ______ in the last examination.
a. should have failed b. have failed c. would fail d. failed
3.虚拟语气用在与表示建议，要求，提议，命令，请求等意思有关的同位语从句和表语从句中，英国英语中要求从句谓语用“ should + 原形动词”，而美国英语中则要求用原形动词， 但在 as if, as though引导的表语从句中，从句中谓语用动词过去式或过去完成式，表示对现在或过去的虚拟。例如：
He complied with the requirement that the experiment (should) be done tomorrow.
他同意明天再做实验的要求。虚拟语气用在其它名词性从句中
He looks as if he were tired.他面带倦容。
We agree to the suggestion that they (should) work on night shifts in turn.
我们同意轮流值夜班的建议。
His order is that you (should) send the materials to the work site at once.
他的命令是你们要把材料立即送到工地。
Example:
Your advice that she ______ till next week is reasonable.
a. will wait b. is going to wait c. waits d. wait
Jane appears as though she ______ the secret.
a. knows b. has known c. had known d. knew
He looked as if he______ ill for a long time.
a. was b. were c. has been d. had been
4.虚拟语气用在 It is (high, about) time (that) 句型中，定语从句中谓语用动词过去式，意指将来。例如：
It is time (that) we went home.
It is high time we had the meeting.
It is time you left.
It is time that I was off.
注：如果主语是单数第一，三人称，动词 be常用 was 。
Example:
We've been sitting here doing nothing about it for days. It's time we ______ the problem.
a. shook hands with b. got to brass tacks with
c. got to grips with d. reached the bottom of
词组 get (or come) to grips with 为“开始努力对付”。
It is high time we _______ off.
a. are b. were c. be d. will be
It is ______ we did something about redecorating the sitting room.
a. high time b. long time
c. good time d. full-time
练习题：
1. The doctor suggested that he ______ a short leave of absence.
a. will take b. would take c. take d. took
2. We demand that atomic weapons ____ .
a. be prohibited b. will be prohibited
c. are prohibited d. ought to be prohibited
3. It was suggested that transistors _____ in such devices.
a. should be used b. should use
c. can be used d. were using
4. The tutor recommended that she _______ this book.
a. must buy b. buy
c. should have bought d. buys
5. The housemaster was strict. He requested that we ______ television on week nights.
a. not watch b. must not to watch
c. not be watching d. have not watched
6. My father did not go to New York, the doctor suggested that he ______ there.
a. not to go b. won't be
c. not go d. not go to
7.I demanded that the students each ______ a plan for the summer vacation.
a. would make b. will make c. make d. made
8. It is surprising enough that such a horrible thing ____ there.
a. happened b. will happen
c. should happen d. has happened
9. It was urgent that she ______ the master immediately.
a. call b. calls c. called d. would call
10. He looks as if he _____ nothing about it before.
a. knows b. had known
c. has known d. wouldn't know
11.My idea is that we ______ the challenge.
a. ought accept b. will accept
c. accept d. are accepted
12. The sun rises in the east and sets in the west, so it seems as if the sun ______ round the earth.
a. is circling b. has circled
c. should circle d. were circling
13. It was suggested at the meeting that effective measures _______ to solve the problem.
a. be taken b. must be taken
c. were taken d. take
14. It's advisable that he ______ with a clearly defined goal in mind.
a. must go b. go c. will go d. goes
15.It seemed as if all of sudden the animal _____ danger in the air.
a. has smelt b. had smelt
c. smelt d. would smell
16.It is better that the book ______ on the low stool.
a. put b. puts
c. should be put d. be put
17.He moved that the report ______.
a. should accept b. should be accepted
c. be accept d. would be accepted
18.The professor gave orders that the test ______ before 5:30.
a. be finished b. will be finished
c. will finish d. shall finish
19.It's time he ______ something for his coming examination.
a. do b. does c. will do d. did
20.It was essential that all the necessary documents ______ to the dean's office before Friday.
a. be handed in b. must be handed in
c. had been handed in d. should hand in
21.It is highly desirable that a new president _____ for our institute.
a. appointed b. be appointed
c. has been appointed d. is appointed
22. The government ordered that the pollution problem of this city ______ within six months.
a. would solve b. would be solved
c. should be solved d. must solve
23. It is natural that much research ______ to overcome corrosion.
a. should make b. will make
c. is made d. should have been made
24. It is important that a consultant engineer ______ familiar with modern developments.
a. is b. being c. be d. has been
25. Since her blood pressure is much higher than it should be, her doctor insists that she _____.
a. will not smoke b. is not smoking
c. didn't smoke d. not smoke
英语语法网：虚拟语气用在条件状语从句中
虚拟语气是一种特殊的动词形式，表示所说的话不是一个事实，而只是一种假设，愿望，建议，怀疑，猜测或不大可能实现的空想。
I.虚拟语气用在条件状语从句中
虚拟语气用在条件状语从句中，通常从句由连词if 引导。
1.与现在事实相反的虚拟条件句
条件状语从句主句
If +主语 +动词过去式主语+ would, should, could, might+原形动词
(be的过去式用were)
例如：
If I feared death, I wouldn't be a communist.
(刘胡兰)怕死就不做共产党员。
If there were no air, we couldn't live.
如果没有空气，我们就不能生活。
Example:
I would ask George to lend us the money if I ______ him.
A. had known B. knew C. have known D. know
I _____ it to him if I thought he would understand.
A. shall explain B. will explain C. would explain D. explain
2.与过去事实相反的虚拟条件句
构成
条件状语从句主句
If + 主语 + 动词过去完成式主语 + would, should, could, might+have + 过去分词
例如：
If you had come a few minutes earlier, you would have met him.
如果你早来几分钟，你就会碰上他。
If there had been no air in the tube, the result of the experiment would have been more accurate.
如果试管中没有空气，实验结果就会更精确。
Example:
If you hadn't gone with Tom to the party last night, _______.
A. you would meet John already
B. you won't have missed John
C. you will have met John
D. you would have met John
3.与将来事实相反的虚拟条件句
构成
条件状语从句主句
If + 主语+ should +原形动词主语+would,should,could,might或were+不定式+原形动词
例如：
If he were to come tomorrow, things would be easier.
假如他明天会来，事情就容易办了。
If the sand should be broken up, it would give out much energy.
如果沙子能被分解，它会释放出大量的能量。
注：在表示与将来事实相反的虚拟条件句中，从句中的should有时可以省略。如：
If he make the design, he might do it in some other way.
要是他来搞这个设计，他可能用另外的方法设计。
Example:
If the sea ____ to rise 50 feet, India would become an island.
A. will B. is C. was D. were
If you ____ to see Mary, what would you tell her?
A. are B. will be going C. must D. were
We might still catch the train if we ___.
A. make hurry B. haste
C. make haste D. hastily
4.错综时间的虚拟语气
在一些含有虚拟语气的句子中，如果主句与从句的谓语表示不同的时间，虚拟语气可有不同形式，即主句与从句各自按自己的时间构成虚拟形式。例如：
If I had met him before, I could recognize him.要是我以前遇见过他，我就能认出他了。
(从句表示与过去事实相反，主句表示与现在或将来事实相反)
If we were driving at a speed of 100 Li an hour, we would have arrived there 2 hours ago. 如果我们的行车速度每小时100里，两小时以前我们就会到达那里了。
(从句与现在事实相反，主句与过去事实相反)
Example:
If you _____ that late movie last night, you wouldn't be sleepy.
A. haven't watched
B. didn't watch
C. hadn't watched
D. wouldn't have watched
5.省略连词if
在条件状语从句中，如果有were, should, had，可以把连词if 省去，把 were, should, had 放在句首，构成条件意义。例如：
Should it rain tomorrow, what would you do? 万一明天下雨，你怎么办?
Were there no friction, we could not walk. 要是没有摩擦力，我们就不能行走。
Had we known about the new method, we should have applied it earlier.
如果我们过去知道这种新方法，我们早就应用了。
Example:
Had Alice been more hardworking, she _______.
A. had not failed B. would not fail
C. could not be failed D. would not have failed
_______ today, he would get there by Friday.
A. Would he leave B. Was he leaving
C. Were he to leave D. If he leaves
______ difficulties, we would be successful.
A. Should we overcome B. Would we overcome
C. Might we overcome D. Could we overcome
6.虚拟结构中省略主句或从句
虚拟结构中有时可省去主句或从句，并不影响意义的完整。
(1)省去条件从句
That would be fine. 那太好了。(省去了if you would come 或类似条件)
I wouldn't pass up the chance to visit China. 我不会放弃访问中国的机会。
We might have produced more coal. 我们可能生产出更多煤炭。
注：省略条件句，在试题中很少见到。
(2)省去主句，常用以表示愿望。从句谓语多用过去时或过去完成时。
If only she were here. 假如她在这儿该多好啊!
If only he lived! 假如他活着该多好啊!
If only I had known it before. 如果我早先知道这件事，那就好了。
Example:
If only it _____! but it is too late.
A. is avoided B. has avoided
C. could be avoided D. can be avoided
If only everything _____ out as we wanted it to in life!
A. is working B. worked
C. works D. has worked
英语语法网：虚拟语气用在其它状语从句中
1.虚拟语气用在由as if, as though 引导的方式或让步状语从句中，一般情况下，如果主谓语动词为现在时，从句谓语多用过去时;如果主句谓语为过去时，从句谓语多用过去完成时。虚拟语气用在 even if, even though, whatever引导的状语从句中，从句谓语可参照由if引导的虚拟条件从句的谓语，一般用过去时或过去完成时。例如：
This old machine runs as if it were a new one.
The old worker works as though he were a young man.
Even though she had been here very soon, she would not catch the train.
Example:
He has just arrived, but he talks as if he ______ all about that.
a. know b. knows c. known d. knew
I can't stand him. He always talks as though he _____ everything.
a. knew b. knows c. has known d. had known
______ I used a lot of examples I still could not get my idea across.
a. Since b. But that c. Now that d. Even though
2.虚拟语气用在so that, lest (唯恐), in case (万一), unless, in order that(为了，以便), that(为了，以至于), for fear that (生怕，以免), on condition that (如果)等引导的目的，条件状语从句中，从句谓语 may 或 might+原形动词，也有用 should, can, could+原形动词构成的。例如：
The teacher explained the law once more in order that we might understand it better.
Some people eat so that they may live. Others seem to live in order that they may eat.
一些人吃是为了生存，而另一些人似乎是活着就是为了吃。虚拟语气用在其它状语从句中
I left him a note with my address on for fear that he should not know where to see me.
The heroes gave their lives that we might live a happy life.
为了我们过上幸福生活，英雄们献出了自己的生命。
Example:
In case I ______, I would try again.
a. will fail b. would miss c. should fail d. shall miss
You should exercise vigilance _____ you should be killed.
a. so that b. lest c. therefore d. that
3.虚拟语气用在由 “whether” 引导的让步状语从句中，从句谓语用原形动词。例如：
All engines work on this principle, whether they be large or small.
所有发动机都按这一原理工作，无论它们是大还是小。
We must finish the work before we go home, whether it be early or late.
无论时间早晚，我们必须在回家前干完工作。
All matter, whether it be gas, liquid or solid, is made up of atoms.
所有物质，不论是气体，液体，或固体，都是由原子构成。
在此句型中，可省去 whether ，而将be放在主语前。例如：
Be it so, we must continue to do the test.
We must do our best to fulfil the task, be it ever so hard.
Example:
______ I'll marry him all the same.
a. Were he rich or poor b. Be he rich or poor
c. Whether rich or poor d. Being rich or poor
练习题：
1.______, I must do another experiment.
a. It is ever so late
b. Ever so late it
c. Be it ever so late
d. Whether be it ever so late
2.The young driver looked over the engine carefully lest it ______ on the way.
a. goes wrong b. would go wrong
c. went wrong d. should go wrong
3.Machines are often oiled so that they ______ well.
a. ran b. runs c. should run d. running
4.Even if he ______ very busy, he would have kept on learning English.
a. had been b. was c. were d. had being
5.Supposing the weather ______ bad, where would you go?
a. is b. will be c. was d. were
6. ______, he could not succeed.
a. However, he tried that
b. He tried however hard
c. However he could try
d. However hard he tried
7. Even though the enemy ______ wings, they couldn't escape from our encirclement.
a. had b. had had c. have d. has
8.She described the accident as if she ______ it herself.
a. saw b. has seen c. had seen d. sees
9.He came to meet us at the station for fear that we ______ the wrong way.
a. take b. should take c. took d. had taken
10.The car looked very dirty, as though it ______ hundreds of miles.
a. run b. runs c. has run d. had run
11.The teacher spoke slowly in order that we ______ no difficulty in following him.
a. should have b. had
c. will have d. didn't have
12.All magnets behave the same, ______ they large or small.
a. how b. are c. be d. were
13.At the beginning he didn't want to speak English lest he _____ mistakes.
a. will make b. should make
c. would make d. can
14. I remember the whole thing as if it ______ yesterday.
a. happen b. happens c. happened d. happening
15.She stayed at home for a few days so that she _____ her mother.
a. takes care of b. took care of
c. might took care of d. might take care of
16.She took up the meter with care for fear that it _____ .
a. is damaged b. to be damaged
c. should be damaged d. was damaged
17. In many cases the heating effect is neglected as if there ______ no flow of current along the wire.
a. are b. were c. is d. being
18.I'll put the money on the table just in case you ______ it.
a. might need b. would need
c. needed d. may have needed
19.Providing you ______ the opportunity to go abroad, which country would you want to visit first?
a. have b. will have c. had d. have had
20.The business of each day, ______ selling goods or shipping them, went quite smoothly.
a. it being b. was it c. it was d. be it
看过英语语法网的相关知识的人还看了：
篇4：英语语法
英语语法
强调：
强调是一种修辞方式，如前面所说的“倒装”就是一种重要的强调手段。
此外，还可以借助助词进行强调，例如：
She did come yesterday; I saw her in the office.
（她昨天确实来了；我在办公室见到她的。）
本讲要讨论的`主要是“it is …。that…”强调句， 即：将句子中除谓语动词以外的成分（主语、宾语、状语等）用“it is …。that…”加以连接，组成强调句，如果是人，也可以用“it is… who…”， 例如：
John bought a toy train for his son yesterday.（昨天约翰给他儿子买了辆玩具火车。）
强调主语：It was John who （或that）bought a toy train for his son yesterday.
强调宾语：It was a toy train that John bought for his son yesterday.
强调宾语（或目的）：It was for his son that John bought a toy train yesterday.
强调时间状语：It was yesterday that John bought a toy train for his son 。
学习强调句要注意以下两点：
不要与主语从句相混淆，例如：我们猜您可能喜欢以下文章： 高考高分生同样热衷出国留学高考后出国留学并非捷径 而是理性选择湖南省最新高考单科王者名单高考后申请澳洲留学的途径高考后最快办理留学美国途径2***年高考：云南考生填报志愿应避开6月30日高峰期2***年高考志愿填报开始 艺术类动漫专业成热门2***年高考志愿填报开始 专家支招高考填志愿2***年高考：如何根据高考分数线划定留学方案20高考：“禁令”之下，状元依旧频现公众视线 英语学习:职称英语考试:职称英语语法之强调与语序
It is well known that light travels in straight lines.
（众所周至，光以直线传播。―― 主语从句）
It was not until the early 18th century that the significance of the event was generally realized.
（直到18世纪初，这一事件的意义才为公众所认识。――强调句）
强调句与主语从句的简单区分是：强调句去掉“it is…that…”，句子结构依然正确，意思不变，如上句：“until the 18th century the significance of the event was not generally realized”。 但是主语从句就不行，如上句：“well know that light travels in straight line”就不通， 句中 “well know” 变成了无依着的成分。
我们猜您可能喜欢以下文章： 高考高分生同样热衷出国留学高考后出国留学并非捷径 而是理性选择2***年湖南省最新高考单科王者名单高考后申请澳洲留学的途径高考后最快办理留学美国途径2***年高考：云南考生填报志愿应避开6月30日高峰期2***年高考志愿填报开始 艺术类动漫专业成热门2***年高考志愿填报开始 专家支招高考填志愿2***年高考：如何根据高考分数线划定留学方案2***年高考：“禁令”之下，状元依旧频现公众视线
篇5：常用英语语法
must 的用法
一、表义务，“必须”。例如：
You must talk to them about their study. 你必须同他们谈谈关于他们学习的事。
二、在否定结构中表不许。例如：
You mustn't leave here. 你不能离开这儿。
三、表推测，暗含有很大的可能性。例如：
He must be ill. He looks so pale. 他肯定是病了。他的脸色那么苍白。
注意：之前我们说过 may 也可以表猜测，但是 may 暗含的可能性较小，must 暗含的可能性较大。另外否定的猜测是用can't。例如：
The baby can't be ill. He is so active. 那宝宝不大可能是病了。他那么活跃。
四、表不可避免，“必然要，必定会”。例如：
All men must die. 人总有一死。
五、表主张，“坚持要，一定要”。例如：
If you must go, at least wait till the rain stops. 如果你坚持要走，至少也要等雨停了再走。
六、关于 must 的简短回答：
-Must I clean the dining room at once? 我必须马上打扫膳厅吗?
-Yes, you must. 是的。
-No, you needn't. / No, you don't have to. 不必马上打扫。
have to 的用法
一、have to 表客观的需要和义务，must 表主观的认识。例如：
I missed the train, so I had to take a taxi. 我没搭上火车，所以我只得打的。(客观上需要打的)
I must study hard. 我必须努力学习。(主观上认为应该努力学习)
二、在疑问句和否定句中，have to 多用助动词 do 构成，must 则直接提前或加not。例如：
Did he have to do it? = Must he do it? 他得做那件事吗?
而且在否定句中，have to 表不需要，must 表不允许：
You don't have to go there. 你不需要去那儿。
You mustn't go there? 你不可去那儿。
篇6：常用英语语法
介词 + 名词(或者代词，或者相当于名词的其他词类、短语、从句)= 介词短语
in the morning 在早晨
under the tree 在树下
from China 来自中国
*注意区别“介词短语”和“短语介词”：
介词短语是(介词 + 名词性短语)，可以单独作为句子成分;
短语介词是(一个相当于介词的短语)，不能单独作为句子成分。
短语介词：
according to 根据
ahead of 在……之前
apart from 在……之外
because of 由于
by means of 以……之手段
by way of 作为
介词短语的位置
一、位于动词之后表示位置
She lives in Shanghai.
她住在上海。
The children are playing in the street now.
现在孩子们在街上玩。
二、位于动词之后表示方向
He went into the kitchen.
他到厨房里去。
三、位于句首表示突出、对照
In the garden everything was so beautiful.
花园里一切都是那么美丽。
四、位于句首，倒装主谓
Behind me lay the fields.
在我的后面是一片田野。
On the desk is a bag.
桌子上有一个袋子。
五、位于名词之后，用于限制前面的名词
The apple on the plate is for you.
盘子上的苹果是给你的。
★ 英语语法知识
★ 英语高级语法
★ 高三英语语法知识
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