Case studies in event-driven control

Case studies in event-driven control

J.H.Sandee1,W.P.M.H.Heemels1,2and P.P.J.v.d.Bosch1

1Eindhoven Univ.of Techn.,P.O.Box513,5600MB Eindhoven,The Netherlands. 2Embedded Systems Institute,P.O.Box513,5600MB Eindhoven,The Netherlands E-mail:{j.h.sandee,m.heemels,p.p.j.v.d.bosch}@tue.nl Abstract.The majority of research in control engineering considers pe-

riodic or time-triggered control systems with equidistant sample inter-

vals.However,practical cases abound in which it is of interest to consider

event-driven control systems,where the sampling is event-triggered.Al-

though there are various bene?ts of using event-driven control like re-

ducing resource usage(e.g.processor and communication load),their

application in practice is hampered by the lack of a system theory for

event-driven control systems.In this paper we present two types of event-

driven controllers and show their potential via industrially relevant case

studies and indicate initial theoretical results.

1Introduction

The majority of research in digital control theory and engineering considers periodic or time-driven control systems in which continuous-time signals are represented by their sampled values at a?xed sample frequency.This leads to equidistant sampling intervals for which the analysis and synthesis problems can be coped with by the vast literature on sampled-data systems.

In most applications,these digital control algorithms are implemented in a real-time embedded software environment.As a consequence of the time-driven nature of controllers,control engineers pose strong,non-negotiable requirements on the real-time implementations of their algorithms as the required control per-formance can only be guaranteed in this manner.In the end,this leads to non-optimal solutions if the design problem is considered from a multi-disciplinary system perspective.As an example,time-driven controllers perform control cal-culations all the time at a?xed high rate,so also when nothing signi?cant has happened in the process.This is clearly an unnecessary waste of resources like processor usage and communication bus load.As a consequence,a time-driven controller might not be optimal,when considered in a broader sense.

To reduce the severe real-time constraints imposed by the control engineer and the accompanying disadvantages,this paper proposes to drop the strict This work has been carried out as part of the Boderc project under the responsibility of the Embedded Systems Institute.This project is partially supported by the Dutch Ministry of Economic A?airs under the Senter TS program.This research was spon-sored by the European6th Framework Network of Excellence HYCON(contract number FP6-IST-511368).

2J.H.Sandee,W.P.M.H.Heemels and P.P.J.v.d.Bosch

requirement of equidistant sampling.The claim is that this enables better multi-disciplinary trade-o?making to achieve a better overall system performance. This type of feedback controllers are called event-driven controllers as it is an event(e.g.the arrival of a new measurement),rather than the elapse of time, that triggers the controller to perform an update.As event-driven control loops typically deal with discrete events with strong interaction with the continuous-time dynamics of the plant,they can be considered as a speci?c class of hybrid systems.

In literature,only few examples of event-driven control have been presented and hardly any theory on control performance analysis can be found.Two good overviews can be found in[1]and[2].To stimulate research in this direction, we consider in this paper two types of event-driven controllers and show their potential via case studies and indicate initial ideas for analyzing the resulting loops.Further details and related research can be found in[3].

2Event-driven control for reducing resource usage

We consider the system described by

˙x(t)=A c x(t)+B c u(t)+E c w(t)(1a)

u(t)=F x(τk),for t∈[τk,τk+1)(1b) where x(t)∈R n is the state,u(t)∈R m the control input and w(t)the unknown disturbance,respectively,at time t∈R+.As a controller a discrete-time state-feedback controller with gain F∈R m×n is considered,i.e.u k=F x k, where x k=x(τk),u k=u(τk)using the zero-order hold u(t)=u k for all t∈[τk,τk+1).

The control update timesτk are in conventional time-driven control related throughτk+1=τk+T s,where T s is a?xed sample time,meaning that the control value is updated every T s time units.To reduce the number of control calculations,we propose not to update the control value if the state x(τk)is contained in a set B around the origin.The control update times are now

τk+1=inf{jT s>τk|j∈N,x(jT s)∈B}.(2) The control objective is a“practical stabilization problem”in the sense of controlling the state towards a region?close to the origin and keeping it there, as asymptotic stability cannot be obtained because the plant is operated in open-loop inside the set B.

The performance of this novel control strategy is addressed in terms of ul-timate boundedness and guaranteed speed of convergence.Depending on the particular event-triggering mechanism used for the control updates,properties like ultimate boundedness for the perturbed event-driven linear system can be derived either from a perturbed discrete-time linear system or from a perturbed discrete-time piecewise linear(PWL)system.Since results for ultimate bound-edness are known for discrete-time linear systems and piecewise linear systems,

Lecture Notes in Computer Science3 these results can be carried over to event-driven controlled systems.In this way we can tune the parameters of the controller to obtain satisfactory control per-formance on one hand and low processor/communication load on the other.An initial experimental case study in paper?ow control in a printer investigates the achievable reduction in the processor load by the particular type of event-driven controllers proposed here[3,Ch.6].In the typical case study,the processor load can be reduced with50%without sacri?cing the control performance signi?-cantly.

3Sensor-based event-driven control

A second line of event-driven control is sensor-based control,which is related to the situation in which the measurement method is intrinsically event-based in nature.Examples are e.g.internal combustion engines that are sampled against engine speed;level sensors for measuring the height of a?uid in a tank;and transportation systems where the longitudinal position of a vehicle is only known when certain markers are passed.We will introduce sensor-based event-driven control via a typical and industrially relevant example of motor control,although the lines of reasoning in this section are more general.

In the case study,we use an(extremely)low resolution encoder to measure the angular position of a motor.The event-driven controller is designed such that actuation is performed at the detection of an encoder pulse.In this way, the controller can use the exact position measurement,and is not a?ected by the quantization errors of the encoder.Moreover,the controller can respond fast to measurement data.When the motor is not running at constant velocity,the updates are not equidistant in time.It is therefore not possible to use classical design methods which assume that updates are equally spaced in time.We can however apply variations on classical design methods if we de?ne our models of the plant and the controller in the(angular)position domain instead of the time domain.This idea is based on the observation that the encoder pulses arrive equally spaced in the position domain.It is shown that,by applying this event-driven controller,we not only decrease the encoder resolution-and therefore the system cost price-but also the average processor load,compared to the originally applied controller in industry.This was accomplished without degrading the control performance.In the typical example of a motor controller applied to transport images through a printer we could accurately control the motor by means of an encoder with a resolution of only1pulse per revolution, with the controller running at an average sample frequency https://www.wendangku.net/doc/0a15443840.html,pared with the originally applied controller,running at a constant sample frequency of 250Hz in combination with an encoder resolution of12pulses per revolution, the processor load was reduced by a factor5.

4J.H.Sandee,W.P.M.H.Heemels and P.P.J.v.d.Bosch

4Conclusions

Although in many practical control problems it is natural and logical to use event-driven controllers,their application is scarce in both industry and academia.

A major reason why time-driven control still dominates is the absence of a sys-tem theory for event-driven control loops.To stimulate research in this direction, this paper presented two types of event-driven controllers with a clear industrial relevance.Given the potential bene?ts of such controllers as shown in the case studies,we believe it is worthwhile to invest research e?ort in this line of work and to develop a mature theory for event-driven control systems. References

1.?A rz′e n,K.E.:A simple event-based PID controller.In:14th World Congress of

IFAC.Volume18.,Beijing,P.R.China(1999)423–428

2.?A str¨o m,K.J.,Bernhardsson,B.M.:Comparison of Riemann and Lebesgue sampling

for?rst order stochastic systems.In:41st IEEE Conference on Decision and Control.

(2002)2011–2016

3.Sandee,J.H.:Event-driven control in theory and practice-trade-o?s in software and

control performance.Phd thesis,Eindhoven Univ.of Techn.,Netherlands(2006)

动名词的用法

动名词的用法及练习 你听过英文语法有动词(verb)、名词(noun)；但你听过有动名词(gerund)吗 1. The girl is singing a song. 2. The girl singing now is my sister. 3. Singing is one of her hobbies(爱好). 一、名词性的动名词(Nominal Gerund) Nominal Gerund 可以加上定冠词(Definite article，如the)或不定冠词(Indefinite article，如a, an)，其他可加在动名词前的还有如：my, this, some, any, all, no 等等。举例如下： 1. The mellow(愉快地) singing of the birds announces the coming of spring. (singing前加定冠词the及形容词mellow；coming 前加the) 2. We knew the robber was near when we heard a faint rustling(沙沙声) in the bushes. (rustling 前加不定冠词a及形容词faint) 从上面的例子可看出如何将一个动词转成名词；但它和真正的名词还是有区别的，那就是没有单数或复数之分。不过，有一些动名词是可以变成真正名词的喔，如：saying, writing, opening, painting, cutting, heading, feeling, being,saving, surrounding, crossing, misunderstanding 等等。它们都可以有复数的喔，方法就是在它们的后面加个s，如：paintings。 二、动词性的动名词(Verbal Gerund) 看看下面的句子： Carelessly writing essays annoys the teacher. 上面的句子里的writing是动名词，但前面有副词carelessly（粗心地），后面又有受词(Object) essays。因此writing就有动词的特征。 注意：Verbal Gerund 这类动名词的前面可不能加上任何冠词(the, a, an ...)喔。 动名词的功能与用法 一、在句子中用作主语(Subject)或主语的补语(Subject Complement): 作主语 1. Listening to music gives me pleasure. (主语Listening ） 2. Running is good exercise. （主语running) 3. Walking to school is a good idea. (主语walking) 作主语的补语 1. My cat's favorite activity is sleeping. (补语sleeping) 2. Seeing is believing. (主语seeing, 补语believing) 主语置于句尾用It + be + ... +v-ing 句型 1. It is fun speaking English. 2. It is of great importance fighting against pollution(污染). 用It is 后接no use. no good, fun 等的句型 1. It is no use learning theory without practice. 2. It is no fun being lost in rain. 用It is 后接useless, nice, good, interesting, worthwhile 等的句型 1. It is worthwhile taking this into consideration. 用There + be + no + v-ing 的句型 1. There is no joking about such matters. 2. There is no getting along with him. (简直无法与他相处) 二、动名词也可以作宾语（Object) 作动词/动词短语的宾语(置于动词或动词短语的后面） 1. I cannot help laughing. （我禁不住笑了起来）（宾语laughing) 2. You should avoid quarrelling with your sister. (宾语quarrelling) 3. You should practice speaking English more. (宾语speaking) 注意：上面三个句子中的动词:help, avoid, practice 只能用动名词作宾语。这类动词还有：dislike 厌恶admit 接受repent 后悔acknowledge 承认

keep 的用法

Keep的用法： keep vt., vi. kept, keeping 保留；保守 I keep old letters.我保存旧信。 I'll keep the original copy of your report on file. 我会把你报告的原件归档的。 It's an interesting suggestion and we'll keep it on ice." 这是一项有趣的建议,我们将留待以后考虑采用。" 保持；继续 We will keep on trying and, if we get anything done, will notify you. 我们将继续努力，有结果将通知你。 Leaders shouldn't keep themselves aloof from the masses. 领导人决不应该脱离群众。 Keep calm!安静! You shouldn't keep chopping and changing like this; you'd better make up your mind right now! "你不能再这样变化无常了,最好现在就拿定主意!" 遵守 He keeps to his promise.他守约。 "Everyone should keep discipline, and you, officers are no exception." "每个人都应该遵守纪律,你们军官也不例外。" 保卫；保护 Keep the baby warm.别把婴儿冻着。（常与from连用）防止；抑制 Keep one's temper。抑制住不发脾气。 Keep a curb on your anger.请抑制住怒气。 扣留；留下 Please keep me a place in the queue.请在队里给我留个位置。 赡养；饲养 to keep a dog养狗 Farmers usually keep chickens in their backyard. 农民们通常在自己的后院养鸡。 经营；经销；管理 to keep a shop开商店 to keep house治家 （常与from连用）远离；不接触 Keep away from the scene of the accident.勿靠近事故现场。 Their dog looked dangerous, we decided to keep our distance from it. 他们家那条狗样子很凶恶,因此我们决定离它远一点。 But the stone walls keep the farmer's cows from joining his neighbor's cows. 但是石头墙使这家农民的母牛不会加入到邻居的牛群中去。

英语语法专项：动名词用法讲解及练习(附答案)

你听过英文语法有动词(verb)、名词(noun)；但你听过有动名词(gerund)吗？ 1. The girl is singing a song. 2. The girl singing now is my sister. 3. Singing is one of her hobbies(爱好). 三个句子中都有singing。第一个句子的singing是常见的现在进行式(Present Continuous)，是说眼下正在做什么；第二个句子的singing是现在分词(Present Participle)，它把sing这个动词转为形容词，但仍有动词的成份（哈哈，这么一说，要把你搞晕了吧:-) 。关于分词，以后有空再谈OK？）。好戏在后头，你看看第三个句子的singing到底是什么东东呀？原来就是我们的主角动名词(Gerund)了！憧矗瑂ing原本是个动词，可是现在它加上ing后，看来竟像是一个名词了。 一、名词性的动名词(Nominal Gerund) Nominal Gerund 可以加上定冠词(Definite article，如the)或不定冠词(Indefinite article，如a, an)，其他可加在动名词前的还有如：my, this, some, any, all, no 等等。举例如下： 1. The mellow(愉快地) singing of the birds announces the coming of spring. (singing前加定冠词the及形容词mellow；coming 前加the) 2. We knew the robber was near when we heard a faint rustling(沙沙声) in the bushes. (rustling 前加不定冠词a及形容词faint) 从上面的例子可看出如何将一个动词转成名词；但它和真正的名词还是有区别的，那就是没有单数或复数之分。不过，有一些动名词是可以变成真正名词的喔，如：saying, writing, opening, painting, cutting, heading, feeling, being,saving, surrounding, crossing, misunderstanding 等等。它们都可以有复数的喔，方法就是在它们的后面加个s，如：paintings。 二、动词性的动名词(Verbal Gerund) 看看下面的句子： Carelessly writing essays annoys the teacher. 上面的句子里的writing是动名词，但前面有副词carelessly（粗心地），后面又有受词(Object) essays。因此writing就有动词的特征。 注意：Verbal Gerund 这类动名词的前面可不能加上任何冠词(the, a, an ...)喔。 动名词的功能与用法 一、在句子中用作主语(Subject)或主语的补语(Subject Complement): 1.1 作主语 1. Listening to music gives me pleasure. (主语Listening ） 2. Running is good exercise. （主语running) 3. Walking to school is a good idea. (主语walking) 1.2 作主语的补语 1. My cat's favorite activity is sleeping. (补语sleeping) 2. Seeing is believing. (主语seeing, 补语believing) 1.3 主语置于句尾 1.3.1 用It + be + ... +v-ing 句型 1. It is fun speaking English. 2. It is of great importance fighting against pollution(污染).

tired的用法总结大全

tired的用法总结大全 tired的用法你知道么?今天给大家带来tired的用法，希望能够帮助到大家，下面就和大家分享，来欣赏一下吧。 tired的用法总结大全 tired的意思 adj. 疲倦的,困倦的,对…不耐烦的,陈旧的 v. (使)疲劳( tire的过去式和过去分词),对(做)某事感到厌倦 变形：副词：tiredly; 比较级：more tired; 最高级：most tired; tired用法 tired可以用作形容词 tired的基本意思是“(身体或精神)疲倦的,困倦的”,形容气力、精力等减少或衰竭,也可表示“陈旧的,陈腐的”; 还可表示“对某人〔某事物〕或做某事不耐烦”,指兴趣减少或衰竭。 美国人常用be tired of表示“厌烦”,英国人则常用be sick of 表示此义。 tired在句中可用作定语或表语,用作表语时一般以人作主语。

tired用作形容词的用法例句 I am not in the least tired.我一点也不疲倦。 If you watch too much TV, youll feel tired.如果你看电视太多,你就会感到疲劳。 We reached our destination, tired and hungry.到达目的地时,我们又累又饿。 tired用法例句 1、You must have noticed how tired he sometimes looks. 你一定注意到他有时候显得特别疲惫。 2、I had a busy day and was rather tired. 今天很忙，我累坏了。 3、What we see at Westminster is a tired old ritual. 我们在威斯敏斯特教堂看到的是一种经年不变的古旧仪式。 词汇精选：tired的用法和辨析 一、详细释义： adj. 疲劳的，累的

英语16种时态表

精心整理|?英语16种时态表 英语时态表 英语时态表 时态 名称 结构常连用的词主要用法例句 一般现在时1由be的 isamare表 示，之后接名 词，形容词或 介词。 every…, sometime s, always,ne ver, often,usu ally等。 一般现在时表示没有时 限的持久存在的习惯性 的动作或状态，或现阶段 反复发生的动作或状态 陈述句：Iamanofficeworker. Heissolazy. Theyareathome 否定句：IamnotTim. Sheisnotverybeauiful. Theyarenotintheoffice. 一般疑问句：Areyouanofficea Isshebeautiful? 2由实意动词 V构成，引导 疑问句和否定 句，用do或 don’t。第三 陈述句：IworkinShanghai. Heworksathome. DavyneverwatchesTVathome

人称时用does或doesn’t,有does出现动词用原形；第三人称陈述句V后加s或es. 否定句:Idon’tlikethefoodinK Davydoesn’tlikethefoodinK 一般疑问句: Doyouwantacupofcoffee?Do ubwaystation? 一般过去时。1由be的过 去式是was或 were表示。 Is\am---was; are---were. ? yesterday , lastweek, anhourag o， thedaybe foreyesterday , in1997。 在过去时间里所发生的 动作或存在的状态。 陈述句：Iwasabigboss.Hewa WewereinBeijinglastyear. 否定句:Iwasnotathomeatthat Wewerenotatworkyesterday 一般疑问句:Wereyouateacher Wassheintheofficelastweek? 2由V的过去 式构成陈述 句，疑问句和 否定句用借助 于did,有did 出现动词用原 陈述句：IworkedinSunmoon WestudiedEnglishthere.Heliv 否定句:Ididn’tworkhere. Theydidn’tseeme.ShelikedE

keep的用法

1.keep +形容词 2.keep+sth/sb +形容词 3.keep +doing 一直做某事 4.keep ... from doing ... 阻止做某事。。。 5.keep a pet 饲养一个宠物 6.How long may I keep this book ？ keep指借。 keep的用法小结 keep是高考常考词汇之一，其含义丰富，与其搭配的短语也很多，其主要用法如下： A、用作及物动词 （1）保留、保存、保持、留下 e.g. We'd better keep a seat for him. 我们最好给他留个座位。 He kept all the money in the bank. 他把所有的钱都存入了银行。 （2）履行（诺言）遵守 e.g. One should keep one's promise. 一个人应当遵守自己的诺言。 Everybody must keep the law. 人人都必须守法。 （3）赡养，养活，饲养 e.g. He has a large family to keep. 他有一大家人要养活。 The old man kept many animals like dogs, pigs and cats. 这位老人养了许多动物，像狗、猪、还有猫等。 （4）经营，管理

e.g. He kept a hotel in this city. 在这座城市里，他开了一家旅店。 She is good at keeping house. 她擅长管理家务。 （5）保守（秘密），记（日记、帐） e.g. All of the people keep the Spring Festival in our country. 我国所有的人都庆祝春节。 Some of them keep birthdays. 他们中有些人庆祝生日。 （7）使……处于某种状态（情况） 在这种情况下，keep常跟复合结构（keep＋宾语＋补语）。用作宾语补足语常见的词有现在分词、过去分词、形容词、副词以及介词短语。 e.g. He kept me waiting for half an hour. 他让我等了半个小时。 Keep your mouth shut and your eyes open. 少说话，多观察。 The doctor kept me in for a week. 医生一周没让我出去。 He always keeps his books in good order. 他总是把书放得整整齐齐。 B、用作不及物动词 （1）保持、继续（处于某种状态）（keep为连系动词）

英语动词用法总结(完整)

英语动词用法总结(完整) 一、单项选择动词 1．The doctor said jokingly that his own infection of the virus _____ the discovery of a vaccine (疫苗)of the disease. A．stood for B．called for C．paid for D．contributed to 【答案】D 【解析】 短语辨析。A.代表 B. 呼吁 C. 为……付出代价 D.导致。句意：医生开玩笑的说，他自己被病毒的感染导致发现了这种病毒的疫苗。故选D。 2．100．----I have been watching “I am a singer” and Gloria Tang (邓紫棋) is my favorite star. ----- Me, too. Her new album is said to be ______ next month. By then, we , fans, will buy some. A．relieved B．delivered C．produced D．released 【答案】D 【解析】D考查动词。句意：--我一直在看“我是一个歌手”而且邓紫棋是我最喜欢的明星。--我也是。她的新专辑将于下月发行。到那时，我们的粉丝们会买一些。A减轻，解除；B 递送；C产生，制造；D发行，发布。故选D。 3．Two lawyers have donated $50,000 to ________ our school’s campaign “Help the Needy”, which was started by our former headmaster three years ago. A．sponsor B．launch C．organize D．plan 【答案】A 【解析】 考查动词辨析。难度中等。 【解题思路】该句意为：两位律师捐赠了5，0000美元赞助我校“帮助贫困生”活动…… A项意为“赞助”，符合句意；B项意为“发射，开办”，C项意为“组织”，D项意为“计划”，都与句意不同。故A项正确。 4．It is beyond awkward when everyone around you ______________ laughing at a joke that you do not find funny, especially if it’s a joke told in a foreign language. A．run into B．bursts out C．yells out D．falls into 【答案】B 【解析】 试题分析：考查动词短语的词义辨析。A.run into快速进入，碰撞；B. bursts out 爆发；C. yells out 大声说出来；D. falls into落入，分成。句意：当你身边的人因一个你不觉得有趣的笑话尤其是用外语来说的笑话而突然爆笑时，你是非常尴尬的。故选B。 考点：考查动词短语的词义辨析

like的用法大全

like的用法大全 今天给大家带来了like的用法，快来一起学习吧，下面就和大家分享，来欣赏一下吧。 喜欢和爱：like的用法大全 I think anybody who falls in love is a freak. Its a crazy thing to do. Its kind of like a form of socially acceptable insanity. ——Her 我觉得陷入爱河的人都是疯子。谈恋爱本来就是件疯狂的事，只不过是大众可以接受的那种。 ——《她》 一、下面我们来看看like有几种含义 adj. 1.相似的having similar qualities to another person or thing The brothers are very like. 这几个兄弟很相像。

2.相同的;同类的closely resembling the subject or original Things which seem to be like may be different. 看来相同的东西实际可能不同。 adv. 1.【口】可能，多半likely, probably 2.同样地;在相同程度上to some extent conj. 好像，如同in the same way as Even though me were friends, it was just like he didnt know me at all. 尽管我们是朋友，他表现得好像根本不认识我。 n. (冠以物主代词)同样的人(或事物);匹敌者a person or thing that is similar to another Have you even heard the like of it? 你听见过这样的事情吗? 2.爱好the things that you like

keep的用法

用作动词(v.) keep about〔around〕1( v.+adv. ) 1. 继续履行职责go on with one's duties keep about〔around〕 She is very ill, but she still keeps about. 她虽然病得很重,但仍然继续工作。 2. 使手边常有have sth always present keep sth ? about〔around〕 I like to keep a few envelopes around in case I need them.我喜欢手边常有几个信封,以应不时之需。 keep about〔around〕2 ( v.+prep. ) keep abreast of( v.+adv.+prep. ) keep after( v.+prep. ) keep aloof( v.+adv. )

keep apart( v.+adv. ) keep at( v.+prep. ) keep away( v.+adv. ) keep away from( v.+adv.+prep. ) keep back( v.+adv. ) keep behind1( v.+adv. ) keep behind2 ( v.+prep. ) keep by1( v.+adv. ) keep by2( v.+prep. ) keep down( v.+adv. ) keep for( v.+prep. ) keep from( v.+prep. ) keep going( v.+adj. ) keep in1( v.+adv. ) keep in2( v.+prep. )

XX届高考英语必修5 Unit 4复习教案

XX届高考英语必修5 Unit 4复习教案XX届高考英语必修5Unit4复习教案 Unit4 makingthenews 制作新闻 核心词汇 ．Everyonewhoisinterestedinthepositionneedsto__ __________theirapplicationsbeforemay5. 2．weshouldtrytofindwaystohelpbeginners____________ thebasicskillsrequiredtolearnanewlanguage. 3．Itwillrequirelotsoftimeto____________theeffectof thenewpolicycarriedoutlastweek. 4.Thecourtyardistoomessyandneedsa____________cleani ng. 5．I____________ofthissuggestionwhichmayhelpourfirm makemoreprofit. 6．Hewasthrownintoa____________wherehecouldn’tputupwiththemanagementbuthedidn’twanttoquitthewell­paidjob.

7．maryistherightpersonwhocanfinishthejobbeforethe_ ___________． 8．____________usassoonaspossibleifanythinghappens. 9．mymotherwaschattingonthephone.____________，myfatherwascookinginthekitchen. 0．Thenovel____________lastmonthwasverypopularwitht eenagers. 1．maryandIhad____________tomeetattheentrancetothez oo，butshefailedtokeepthe____________，whichmademevery angry. 2．用admire的适当形式填空 whilestillatprimaryschool，Rowanhadalreadyshown____________talent. Shestoodatthewindow，lookingattheskirtwith____________. chinaandjapanhavemid­autumnfestivals，whenpeople____________themoonandinchina，enjoymooncakes.

最新英语非谓语动词用法总结(完整)

最新英语非谓语动词用法总结(完整) 一、单项选择非谓语动词 1．Students surf the internet _______ more information about the university they are dreamt of. A．found B．finding C．having found D．to find 【答案】D 【解析】考查非谓语动词。句意：学生们上网是为了找到他们理想大学的更多的信息。此处表示目的用不定式，指上网的目的。故选D。 2．Look over there! There is a long, winding path ________ up to the house. A．lead B．leading C．led D．to lead 【答案】B 【解析】 【详解】 考查非谓语动词。句意：看那边!有一条长长的蜿蜒小路通向那所房子。分析句式可知，这是个there be 句型，因此，此处用非谓语动词，path与lead是主动关系，因此用现在分词，故选B。 3．______ to nuclear radiation, even for a short time, may influence genes in human bodies. A．Having exposed B．Being exposed C．To expose D．Exposed 【答案】B 【解析】 【详解】 考查动名词。句意：暴露于核辐射中甚至很短时间都会影响人体的基因。分析句子成分发现even for a short time是插入语，may influence是谓语，前面的部分应该是主语，be exposed to“暴露于”，要用动名词Being exposed to。故B选项正确。 4．The lecture, _______at 7:00 pm last night, was followed by an observation of the moon with telescopes. A．starting B．being started C．to start D．to be started 【答案】A 【解析】 选A start与逻辑主语the lecture之间为主动关系，故排除B、D两项。不定式作定语时，常表示动作尚未发生，故排除C项，此处用现在分词作后置定语，表示主动。 第四步：根据与谓语动词的先后关系确定时态 非谓语动词表示的动作发生在谓语动词表示的动作之前用过去分词或v.-ing形式/不定式的

like 的用法

“like”前与后-like的用法 like 表示“喜欢”，我们在使用时要重点注意它的前前后后。 I．like前 like和其它行为动词一样，在肯定句中，主语是第一人称、第二人称以及第三人称复数时谓语动词一般现在时用原形，但第三人称单数时要加词尾-s，如：Many people like science. 很多人喜欢科学。 My teacher likes reading books. 我的老师喜欢读书。 但变为疑问句和否定句时要注意： 1. 主语是第一人称（单数和复数）I、we、第二人称you以及第三人称复数they、Li Ping and Mary、the desks等，变为疑问句和否定句时要借助助动词do，谓 语动词不变。如： I like table tennis very much. → Do you like table tennis very much. They like playing basketball. → They don’t like playing basketball. 2. 主语是第三人称单数时，变为疑问句和否定句时要借助助动词does，谓语动 词改为原形。如： Mary l ikes pizza. → Mary doesn’t like pizza. He likes to play the piano. → Does he like to play the piano? II．like后 1. like后跟可数名词表示类别时，名词通常用复数形式，不用单数形式。如： Mary likes dumplings. 玛丽喜欢饺子。 2. like后跟不可数名词时，名词通常用原形。如： Mike doesn’t like pizza. 迈克不喜欢比撒饼。 3. like后跟动词，要用-ing形式。 I like taking photos. 我喜欢照相。 4. like后跟动词，也可用to do形式。 Do you like to play computer games? 你喜欢玩电脑游戏吗？ 注意：通常情况下用-ing形式和to do形式没有较大区别，可互相换用。但有时用-ing形式表示习惯性动作，而用to do形式表示具体的一次动作 like作动词时，意为“喜欢”。常见用法有以下两种： ①“like + 名词 / 代词”表示“喜欢某人或某物”。例如： She likes her students very much. 她非常喜欢她的学生。 This is my computer. I like it a lot. 这是我的电脑，我非常喜欢它。 ②like doing sth.和like to do sth.都表示“喜欢做某事”。like doing sth.着重于习惯、 爱好；like to do sth.着重某次具体的行为或动作。例如： I like reading, but I don’t like to read this evening.

常见介词用法

常见介词用法： 1）at,in,on在……范围 at(1)表示在小地方;(2)表示“在……附近，旁边” in(1)表示在大地方;(2)表示“在…范围之内”。 on表示毗邻，接壤 to表示在……范围外，不强调是否接壤Hearrivedatthestationatt en. Heissittingatthedesk. HearrivedinShanghaiyes terday. JiangsuliesintheeastofCh ina. RussialiveonthenorthofC hina. FujianistothesouthofJian gsuProvince. 2)above,over,on在……上 above指在……上方,不强 调是否垂直，与below相 对； over指垂直的上方,与 under相对,但over与物体 有一定的空间，不直接接 触。 on表示某物体上面并与之 接触。 Thebirdisflyingabovemy head. Thereisabridgeovertheri ver. Heputhiswatchonthe 3)below,under在……下面 under表示在…正下方 below表示在……下，不一 定在正下方 Thereisacatunderthetabl e. Pleasewriteyournamebel owtheline. 介词短语组织形式及实例： 一、介词+名词形式 第一组 byaccident偶然 onaccountof因为，由于 inaddition另外 inadditionto除……之外 intheair在流行中，在传播 中

Keep_用法

Keep 用法知多少 keep 是英语中用法灵活的动词之一，用法归纳如下： 一、用作系动词，意为“保持（某种状态）”，其后常接形容词作表语。如： Please keep quiet / silent! 请保持安静！ After the accident, he still kept alive. 这次事故之后，他仍然活着。 二、用作实义动词，可表示： 1. 保管；保存；保留。如： Keep the change. 零钱不用找了。 Please keep these things for me while I am away. 在我离开期间，请你替我保管这些东西。 2. 赡养；饲养。如： Does he earn enough to keep himself and his family? 他的收入够养活他自己和他的家人吗？ I used to keep sheep in my childhood. 我在孩提时常常养羊。 3. 经营。如： Her father kept a grocer's shop for a number of years. 她父亲开了几年杂货店。 4. 坚持；继续。后面如接动词，要用V-ing 形式作宾语。如： If you keep (on) practising your spoken English, you'll soon make great progress. 如果你坚持练习英语口语，你很快就会取得很大的进步。 5. 阻止；阻碍。常用于keep sb/sth from doing sth 结构中，其中介词from 不能省略。如： The heavy rain didn't keep them from watching the football match. 大雨没能阻止他们观看足球赛。 6. 保持。其后常接复合宾语，表示使（某人或某物）保持某种状态或使某一动作继续。 ①keep + sb/sth + 介词。如：

with用法小结

with用法小结 一、with表拥有某物 Mary married a man with a lot of money . 马莉嫁给了一个有着很多钱的男人。 I often dream of a big house with a nice garden . 我经常梦想有一个带花园的大房子。 The old man lived with a little dog on the lonely island . 这个老人和一条小狗住在荒岛上。 二、with表用某种工具或手段 I cut the apple with a sharp knife . 我用一把锋利的刀削平果。 Tom drew the picture with a pencil . 汤母用铅笔画画。 三、with表人与人之间的协同关系 make friends with sb talk with sb quarrel with sb struggle with sb fight with sb play with sb work with sb cooperate with sb I have been friends with Tom for ten years since we worked with each other, and I have never quarreled with him . 自从我们一起工作以来，我和汤姆已经是十年的朋友了，我们从没有吵过架。 四、with 表原因或理由 John was in bed with high fever . 约翰因发烧卧床。 He jumped up with joy . 他因高兴跳起来。 Father is often excited with wine . 父亲常因白酒变的兴奋。 五、with 表“带来”，或“带有,具有”，在…身上，在…身边之意

Like用法归纳

【Like用法归纳】 like 一词具有多种词性和词义，以及多种用法。 VJ 用作动词（V.）,意思为”爱，爱好，喜欢”，无进行时态，既表示对人或者事物的真挚的感情, 又表示”对某事有着浓厚的兴趣、爱好”。后面可以接名词、代词、动名词或者不定式。1」ike+名词/代词，意为”喜欢某人或某物”。 汤姆非常喜欢鱼。 王老师是个好老师，我们都喜欢他。 我的小弟弟非常喜欢草莓。 2」ike to do sth. 意为”喜欢做某事（偶尔的、一次性的具体的行为）” It is too hot, I like to swim today. 今天太热了，我想去游泳。（只有今天想去，一次性的行为） 今天我想和你聊一下。 3.like doing sth. 意为”喜欢做某事（经常或习惯地）”。例如： It is too hot, I like swimming in summer. 天太热了，整个夏天我都喜欢去游泳。（表示”经常性的动作”，已经形成习惯） He likes sin gi ng. 他喜欢唱歌。 The boy likes wash ing hands in cold water. 这个男孩喜欢在冷水里洗手。 4.like sb. to do sth .意为”喜欢某人做某事”。例如： Our En glish teacher likes us to ask questio ns. 我们的英语老师喜欢我们提问。 5. would like to do sth. (=want to do sth.) 意为”想要做某事”。例如: rd like to go shoppi ng with you. 我想要和你一起去买东西。 6. would like sb. to do sth. 意为”想要某人做某事”。 rd like you to meet my pare nts. 我想要你见见我的父母亲。 like sb. to do sth. 喜欢某人做某事女口：① ②③ prep. be like/ look like +名词或代词作宾语，意为”像??…;跟??…一样”。例如:

常见介词用法

常见介词用法 集团文件发布号：（9816-UATWW-MWUB-WUNN-INNUL-DQQTY-

常见介词用法： 1）at,in,on在……范围 at(1)表示在小地方;(2)表示“在……附近，旁边” in(1)表示在大地方;(2)表示“在…范围之内”。 on表示毗邻，接壤 to表示在……范围外，不强调是否接壤Hearrivedatthestati onatten. Heissittingatthedes k. HearrivedinShanghai yesterday. Jiangsuliesintheeas tofChina. Russialiveonthenort hofChina. Fujianistothesoutho fJiangsuProvince. 2)above,over,on 在……上 above指在……上方, 不强调是否垂直，与 below相对； over指垂直的上方, 与under相对,但 over与物体有一定的 空间，不直接接触。 on表示某物体上面并 与之接触。 Thebirdisflyingabov emyhead. Thereisabridgeovert heriver. Heputhiswatchonthe 3)below,under 在……下面 under表示在…正下 方 below表示在…… 下，不一定在正下方 Thereisacatunderthe table. Pleasewriteyourname belowtheline. 介词短语组织形式及 实例： 一、介词+名词形式

第一组 byaccident偶然onaccountof因为，由于 inaddition另外inadditionto除……之外 intheair在流行中，在传播中 on(the/an)average 平均，一般来说onthebasisof根据，在……的基础上 at(the)best充其量，至多forthebetter好转，改善onboard在船(车、飞 机)上 outofbreath喘不过 气来 onbusiness因公，因 事 inanycase无论如 何，总之 incaseof假使，万一 incase假如，以防 (万一)免得 innocase决不 第二组 bychance偶然，碰巧 incharge(of)负责， 主管 (a)roundtheclock昼 夜不停地 incommon共用，共 有，共同 inconclusion最后， 总之 onconditionthat 在……条件下 inconfidence信任 inconnectionwith/to 关于 inconsequence因 此，结果 inconsequenceof由 于……的缘故 onthecontrary反 之，正相反 incontrastwith/to 与……成对照 outofcontrol失去控 制