What Causes Hearing Loss

What Causes Hearing Loss

Noise, not age is the leading cause of hearing loss. Unless you take steps now to protect to your ears, sooner or later many of you — and your children — will have difficulty understanding even ordinary speech.

Tens of millions of Americans, including 12 percent to 15 percent of school-age children, already have permanent hearing loss caused by the everyday noise that we take for granted as a fact of life.

“The sad truth is that many of us are responsible for our own hearing loss,” writes Katherine Bouton in her new book, “Shouting Won’t Help: Why I — and 50 Million Other Americans —Can’t Hear Y ou.” The cause, she explains, is “the noise we blithely subject ourselves to day after day.”

While there are myriad regulations to protect people who work in noisy environments, there are relatively few governing repeated exposure to noise outside the workplace, from portable music devices, rock concerts, hair dryers, sirens, lawn mowers, leaf blowers, vacuum cleaners, car alarms and countless other sources.

We live in a noisy world, and every year it seems to get noisier. Ms. Bouton notes that the noise level inside Allen Fieldhouse at the University of Kansas often exceeds that of a chain saw.

After poor service, noise is the second leading complaint about restaurants. Proprietors believe that people spend more on food and drink in bustling eateries, and many have created new venues or retrofitted old ones to maximize sound levels.

When I’m told about a new restaurant, my first question is, “Is it noisy?” My friends and I will never return to one in which the racket makes it impossible to converse with tablemates. Perhaps the young d iners the restaurateurs covet “talk” by texting.

The ears are fragile instruments. When sound waves enter the ear, they cause the eardrum to vibrate. The vibrations are transmitted to the cochlea, in the inner ear, where fluid carries them to neatly organized rows of hair cells. These in turn stimulate auditory nerve fibers, each attuned to a different frequency. These impulses travel via the auditory nerve to the brain, where they are interpreted as, say, words, music or an approaching vehicle.

Damage to this delicate apparatus results from both volume and length of exposure to sound. V ery loud noises, or chronic exposure to sound even when it is not particularly loud, can wreak havoc on hair cells, causing them to become disarranged and to degenerate.

We are born with a fixed number of hair cells; once they are dead, they cannot be replaced, and auditory sensitivity is permanently lost. Usually, sensitivity to high-frequency sounds is first to go, followed by an inability to hear the frequencies of speech.

Furthermore, the effects of noise exposure are cumulative, as Robert V. Harrison, an auditory specialist at the University of Toronto, noted recently in the International Journal of Pediatric s. Although we start out with a redundancy of hair cells, with repeated noisy insults, enough are destroyed to impair hearing. Thus, damage to hair cells incurred early in life, as has happened to many rock musicians and rock concert aficionados, can show up in midlife as difficulty understanding speech.

Sound volume is measured in decibels (dB), and the level at which noise can cause permanent hearing loss begins at about 85 dB, typical of a hair dryer, food processor or kitchen blender.

Dr. Michael D. Seidman, the director of otolaryngology at Henry Ford West Bloomfield Hospital

in Michigan, told me to use ear plugs when I dry my hair or mow my lawn with a gas-powered mower, and to cover my ears when an emergency vehicle passes with siren blasting. Ear protection is a must for people who shoot guns as well as those who ride motorcycles or use snow blowers, leaf blowers, hand or pneumatic drills or chain saws.

But even noisier than many of these is the maximum output of some portable music players, which can exceed occupational safety levels and produce sound levels in the ear on a par with that of a jet taking off. If you listen to music with earbuds or headphones at levels that block out normal discourse, you are in effect dealing lethal blows to the hair cells in your ears, Dr. Seidman said.

A national study in 2006 by the American Speech-Language-Hearing Association found that among users of portable music devices, 35 percent of adults and up to 59 percent of teenagers reported listening at loud volumes.

Dr. Harrison urges purchasers of such “personal entertainment devices” to read and heed the warnings and practical advice on package inserts. Too often people turn up the volume to overcome surrounding noise. A better plan is to set a maximum volume while in a quiet environment and never go above that.

In general, if other people can hear what you’re listening to, the volume is turned up too high. Many times I’ve had to change my seat on the subway or bus because the rider next to me was using a music player as if it were a boombox.

Some portable listening devices come with the ability to set a maximum volume, which may be worth the added cost to parents concerned about protecting their children’s ears.

At a given volume level, earbuds deliver higher noise levels than over-the-ear headphones. If earbuds are used, Dr. Harrison suggests selecting ones that fit loosely and never inserting them tightly into the ear canal. Alternatively, when you are alone and not at risk of missing important environmental cues, like an approaching vehicle, consider using noise-canceling over-the-ear headphones that block out background noise and enable you to listen at a lower volume.

Even toys meant for young children can generate ear-damaging levels of noise. The American Speech-Language-Hearing Association lists as potential hazards cap guns, talking dolls, vehicles with horns and sirens, walkie-talkies, rubber squeaky toys, musical instruments and toys with cranks. According to the association, some toy sirens and squeaky rubber toys can emit sounds of 90 decibels, as loud as a lawn mower.

It suggests that parents with normal hearing test new toys before giving them to a child. “If the toy sounds loud, don’t buy it,” is the recommendation. For noisy toys already bought, consider removing the batteries or taping over the speaker.

Additional protective information can be found online. Check out It’s a Noisy Planet; Keep It Hear; Listen to Y our Buds; Hear-It Y outh; and Dangerous Decibels.

WHEN与WHILE用法区别

WHEN与WHILE用法区别 when, while这三个词都有"当……时候"之意，但用法有所不同，使用时要特别注意。 ①when意为"在……时刻或时期"，它可兼指"时间点"与"时间段"，所引导的从句的动词既可以是终止性动词，也可是持续性动词。如： When I got home, he was having supper.我到家时，他正在吃饭。 When I was young, I liked dancing.我年轻时喜欢跳舞。 ②while只指"时间段"，不指"时间点"，从句的动词只限于持续性动词。如：While I slept, a thief broke in.在我睡觉时,盗贼闯了进来。 辨析 ①when从句与主句动作先后发生时，不能与while互换。如： When he has finished his work, he takes a short rest.每当他做完工作后，总要稍稍休息一下。(when = after) When I got to the cinema, the film had already begun.当我到电影院时，电影已经开始了。(when=before) ②when从句动词为终止性动词时，不能由while替换。如： When he came yesterday, we were playing basketball.昨天他来时，我们正在打篮球。 ③当从句的谓语是表动作的延续性动词时，when, while才有可能互相替代。如：While / When we were still laughing, the teacher came in.正当我们仍在大声嬉笑时，老师进来了。 ④当从句的谓语动词是终止性动词，而且主句的谓语动词也是终止性动词 时,when可和as通用，而且用as比用when在时间上更为紧凑，有"正当这时"的含义。如： He came just as (or when) I reached the door.我刚到门那儿，他就来了。 ⑤从句的谓语动词如表示状态时，通常用while。如： We must strike while the iron is hot.我们应该趁热打铁。 ⑥while和when都可以用作并列连词。

(易错题精选)初中英语词汇辨析的单元汇编含答案解析

一、选择题 1．I’d like to________the mall because it’s crowded and noisy. A．visit B．hang out C．walk D．go off 2．That path ________ directly to my house.You won't miss it. A．leads B．forms C．repairs D．controls 3．I don’t want to go. __________, I am too tired. A．However B．And C．Besides D．But 4．Some animals carry seeds from one place to another, ________ plants can spread to new places. A．so B．or C．but D．for 5．When I as well as my cousins __________ as a volunteer in Beijing, I saw the Water Cube twice. A．were treated B．treated C．was served D．served 6．He is wearing his sunglasses to himself from the strong sunlight. A．prevent B．stop C．keep D．protect 7．When you are________, you should listen to music to cheer you up. A．shy B．afraid C．strict D．down 8．Mr. Smith gave us some________on how to improve our speaking skills. A．advice B．news C．knowledge D．information 9．World Book Day takes place ________ April 23rd every year. A．at B．in C．on 10．More and more people have realized that clear waters and green mountains are as ________ as mountain of gold and silver. A．central B．harmful C．valuable D．careful 11．We loved the food so much, ________the fish dishes. A．special B．especial C．specially D．especially 12．—Oh, my God! I have ________ five pounds after the Spring Festival. —All of the girls want to lose weight, but easier said than done. A．given up B．put on C．got on D．grown up 13．—What do you think of the performance today? —Great! ________ but a musical genius could perform so successfully. A．All B．None C．Anybody D．Everybody 14．He ________ his homework________the morning of Sunday. A．doesn’t do; on B．doesn’t do; in C．doesn’t; on 15．Maria ________ speaks Chinese because she doesn’t know much Chinese. A．seldom B．always C．often D．usually 16．In 2018, trade between China and Hungary rose by 7.5 percent, and recently on Friday companies from China and Hungary________ several cooperation (合作) agreements under the

when 和 where 引导定语从句的用法

when 和 where 引导定语从句的用法 定语从句既是英语语法的一个重点，同时又是一个难点。说它是难点，主要难在两点上：一点是如何正确判断什么样的汉语句子要译为英语的带定语从句的复合句；另一点是定语从句的引导词较多(包括关系代词who, that, which, as 和关系副词when, where, why)，而且其用法也较复杂。那么到底什么情况下用when和where来引导定语从句呢？它们又该怎么用呢？下面就举例说明： 一、when：当主句中的先行词(即主句中被后面定语从句修饰的词)是表示时间意义的名词时，它只能作定语从句的时间状语，放在定语从句句首。如果定语从句的引导词是作该定语从句的主语或宾语，则要改用关系代词that或which来引导。例如： The days when we used foreign oil are gone. 我们用洋油的日子一去不复返了。 I'll never forget the day when I was born. (=I'll never forget my birthday.) 我永远不会忘记我出生的日子。 It happened in November when the weather was wet and cold. 这事发生在天气又湿又冷的十一月。 In the years that (which) followed, Marx kept on studying English and using it. 在这之后的几年中，马克思继续学习和使用英语。(that作定语从句"that followed"的主语) The day (that) I always remember in all my life is my birthday. 我一生中最难忘的日子是我的生日。(that作定语从句"that I always remember in all my life"的宾语，that可以省略)

When引导的定语从句与时间状语从句的区分

一、从句是如何出题的？ 1. 时态 2. 考连接词 3. 考语言顺序 二、学好从句的两个基本条件 1. 时态 2. 从句的三个必须:①必须是句子；②必须有连接词；③必须是陈述句 三、状语从句、宾语从句、定语从句重点 1.如何判断何种从句 2. 从句的时态 3. 从句的连接词与扩展 4. 经典单选、从句与选词、长句子分析 四、如何判断三种从句 1. 状语从句无先行词 2. 宾语(表语)从句无先行词有动词或词组 3. 定语从句先行词多为名词或代词 一、When引导的定语从句与时间状语从句的区分 1. when的译法不同。在时间状语中，when 翻译成“当……的时候” I want to be a teacher when I grow up. 当我长大的时候，我要做一名老师。在定语从句中，when不翻译。I won't forget the day when he says he loves me. 我不会忘记他说爱我的那一天。 2. 在时间状语中，when从句前面或后面是句子；定语从句中，when 从句不能位于句首，且通常when前为表示时间的名词day、year等。 3. when在从句的作用不同。在时间状语从句中，when是连词，只起连接主句和从句的作用，不做从句的任何成分。不过when引导的时间状语从句修饰主句的谓语，做主句的时间状语。 在定语从句中，when是关系副词，在从句中代替先行词做从句的时间状语，修饰从句的谓语。 例1 I will always remember the days when I lived with my

grandparents in the country. 例2 I always remember the days in the country when I see the photo of my grandparents. 点评：例1意为“我会永远记得跟我祖父母一起住在乡下的那些日子”，其中when 引导的是一个定语从句, 修饰the days, when在从句中作时间状语。例2意为“当我看到祖父母的照片时，总是会想起在乡下的那些日子”，其中when 引导的从句并不修饰前面的名词the country，因此可判定为时间状语从句。 例1中的when可用in which替代，即从句可改为...in which I lived with my grandparents in the country. 例2中从句前有名词，但根据句意可 知并不是从句所修饰的对象，也不能用“介词+ which”来替代。 二、判断关系代词与关系副词 方法一：用关系代词，还是关系副词完全取决于从句中的谓语动词。及物动词后面无宾语，就必须要求用关系代词；而不及物动词则要求用关系副词。例如： This is the mountain village where I stayed last year. 这是我去年呆过的山村。 I'll never forget the days when I worked together with you. 我永远不会忘记与你共事的日子。 判断改错： 1. This is the mountain village where I visited last year. 2. I will never forget the days when I spent in the countryside. 3. This is the mountain village （which）I visited last year.

过去进行时、when和while引导时 间状语从句的区别

过去进行时过去进行时表示过去某一时刻或者某段时间正在进行或发生的动作，常和表过去的时间状语连用，如： 1. I was doing my homework at this time yesterday. 昨天的这个时候我正在做作业。 2. They were waiting for you yesterday. 他们昨天一直在等你。 3. He was cooking in the kitchen at 12 o'clock yesterday. 昨天12点，他正在厨房烧饭。 过去进行时的构成： 肯定形式：主语+was/were+V-ing 否定形式：主语+was not (wasn't)/were not (weren't)+V-ing 疑问形式：Was/Were+主语+V-ing。 基本用法： 1. 过去进行时表示过去某一段时间或某一时刻正在进行的动作。常与之连用的时间状语有，at that time/moment, (at) this time yesterday (last night/Sunday/week…), at+点钟+yesterday (last night / Sunday…)，when sb. did sth.等时间状语从句，如： 1）What were you doing at 7p.m. yesterday? 昨天晚上七点你在干什么？ 2）I first met Mary three years ago. She was working at a radio shop at the time. 我第一次遇到玛丽是在三年前，当时她在一家无线电商店工作。 3）I was cooking when she knocked at the door. 她敲门时我正在做饭。 2. when后通常用表示暂短性动词，while后通常用表示持续性动词，而while所引导的状语从句中，谓语动词常用进行时态，如： When the car exploded I was walking past it. = While I was walking past the car it exploded. 3. when用作并列连词时，主句常用进行时态，从句则用一般过去时，表示主句动作发生的过程中，另一个意想不到的动作发生了。如： I was walking in the street when someone called me. 我正在街上走时突然有人喊我。 4. when作并列连词，表示“（这时）突然”之意时，第一个并列分句用过去进行时，when引导的并列分句用一般过去时。如：

boring 令人厌烦的

boring 令人厌烦的，乏味的，无聊的 tedious 乏味的，单调的，冗长的 flat 单调的，沉闷的 dull 乏味的，单调的 troublesome 令人烦恼的，讨厌的，麻烦的 tired 疲劳的，累的 bored 无聊的，无趣的，烦人的 exhausted 极其疲倦的 weary 疲劳的 bright 聪敏的，机灵的 apt 聪明的，反应敏捷的 intelligent 聪明的，有才智的 shrewd 机灵的，敏锐的，精明的（表示生意上的精明） ingenious （人，头脑）灵巧的 alert 警觉的，留神的 cute 聪明伶俐的，精明的 acute/cute acute 指的是视力，感觉的敏锐 dull 愚钝的，笨的 awkward 笨拙的，不灵巧的 absurd 荒谬的 ridiculous 可笑的，荒谬的 idiotic 白痴般的 blunt 率直的，直言不讳的 clumsy 笨拙的，粗陋的 happy 快乐的，幸福的 cheerful 欢乐的，高兴的 content 满意的，满足的 merry 欢乐的，愉快的，快乐的 pleasure 高兴，愉快，满足 enjoyment 享乐，快乐，乐趣 cheer 喝彩 applause 鼓掌，掌声 optimism 乐观，乐观主义 delight 快乐，高兴 kick 极大的乐趣 paradise 天堂，乐园 instant 立即的，即刻的 instantaneous 瞬间的，即刻的 immediate 立即的，即刻的 simultaneous 同时发生的，同时存在的，同步的punctual 严守时刻的，准时的，正点的 pick 挑选，选择 select 选择，挑选 single 选出，挑出 elect 选举，推举 vote 投票，选举 appoint 任命，委派 nominate 提名，任命 propose 提名，推荐 recommend 推荐，举荐 designate 指派，委任 delegate 委派（或选举）…为代表 install(l) 使就职，任命 ballot 使投票表决 dub 把…称为 choice 选择（权） option 选择 selection 选择，挑选 alternative 取舍，供选择的东西 favorite 特别喜爱的人（或物） inclination 爱好 preference 喜爱，偏爱，优先 observe 注意到，察觉到 perceive 认识到，意识到，理解 detect 察觉，发现 appreciate （充分）意识到，领会，体会 alert 使认识到，使意识到 awake 意识到，醒，觉醒 scent 察觉 ancient 古代的，古老的 primitive 原始的 preliminary 预备的，初步的 preliminary trial初审 primary 最初的，初级的 initial 开始的，最初的 original 起初的 former 在前的，以前的 previous 先，前 prior 在前的，优先的 beforehand 预先，事先 medieval 中世纪的，中古（时代）的preceding 在先的，在前的，前面的 senior 资格较老的，地位较高的 following 接着的，下述的 attendant 伴随的 subsequent 随后的，后来的 succeeding 以后的，随后的 consequent 作为结果（或后果）的，随之发生的 resultant 作为结果的，因而发生的therefore 因此，所以 consequently 所以，因此 then 那么，因而 thus 因此，从而 hence 因此，所以 accordingly 因此，所以，于是 thereby 因此，从而

when 和while的用法区别

when 和while的用法区别 ①when是at or during the time that, 既指时间点，也可指一段时间； while是during the time that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while从句中的动词必须是延续性动词。 ②when 说明从句的动作和主句的动作可以是同时，也可以是先后发生；while 则强调主句的动作在从句动作的发生的过程中或主从句两个动作同时发生。 ③由when引导的时间状语从句，主句用过去进行时，从句应用一般过去时；如果从句和主句的动作同时发生，两句都用过去进行时的时候，多用while引导，如： a. When the teacher came in, we were talking. 当此句改变主从句的位置时，则为： While we were talking, the teacher came in. b. They were singing while we were dancing. ④when和while 还可作并列连词。when表示“在那时”；while表示“而，却”，表对照关系。如： a. The children were running to move the bag of rice when they heard the sound of a motor bike. 孩子们正要跑过去搬开那袋米，这时他们听到了摩托车的声音。 b. He is strong while his brother is weak. 他长得很结实，而他弟弟却很瘦弱。 when，while，as引导时间状语从句的区别 when，while，as显然都可以引导时间状语从句，但用法区别非常大。 一、when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。 ①Why do you want a new job when youve got such a good one already？（get 为短暂性动词）你已经找到如此好的工作，为何还想再找新的？ ②Sorry，I was out when you called me．（call为短暂性动词）对不起，你打电话时我刚好外出了。 ③Strike while the iron is hot．（is为延续性动词，表示一种持续的状态）趁热打铁。 ④The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。 二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while和as从句的谓语动作必须是和主句谓语动作同时发生。 1．从句动作在主句动作前发生，只用when。 ①When he had finished his homework，he took a short rest．（finished先发生）当他完成作业后，他休息了一会儿。 ②When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时，客人们已经离开了。 2．从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。

boring 和bored的区别

不能片面说人做主语用ed，物做主语ing ing形式是修饰引起这种感觉的人或物；ed形式是描写人或物的感受。（当然物一般是动物） 翻译的话 ing形式的词译为“令人……的”；ed形式译为“……的” boring是令人感到厌烦的；bored是厌烦的。 a boring person 能够指一个了无情趣的人，让人觉得无趣的人 a bored person 则是说这个人自己感到很无趣 1.bore 1）vt.使厌烦；挖 e.g. I'm bored with this job. 这件工作厌烦了。 The oldier bore the sharp pain in the wound with great courage. 这士兵以巨大的勇气忍受着伤口的剧烈疼痛。 2）n.令人讨厌的人（或事） e.g. It's a bore having to go out again. 外出真是讨厌。 boredom n.厌倦，无趣 e.g. in infinite boredom 极其无趣 boring n. 钻(孔) adj. 令人厌烦的(事或物） e.g. The play was boring. 这部短剧很一点意思都没有。 bored adj. 无聊的, 无趣的, 烦人的 e.g. Jack is so bored. 杰克是个没有趣的人。 2.surprising 是针对事或物感到惊奇。 surprised 则是针对人。 3.pleasant adj. 愉快的, 快乐的, 舒适的, 合意的可爱的, 举止文雅的, 活泼的滑稽的, 有趣的 (天气)晴朗的, 美好的容易相处的, 友爱的 e.g. a pleasant voice 悦耳的声音 a pleasant companion 可爱的伴侣 a pleasant time 愉快地度过时光 pleasing adj. 舒适的, 使人愉快的; 满意的; 惹人喜欢的, 可爱的 e.g. a pleasing look 使人愉快的神情 a very well mannered and pleasing young man 彬彬有礼而令人喜爱的年轻人

when while用法区别

While和When在过去进行时中两者的区别如下： ①when是at or during the time that, 既指时间点，也可指一段时间；while是during the time that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while 从句中的动词必须是延续性动词。 ②when 说明从句的动作和主句的动作可以是同时，也可以是先后发生；while 则强调主句的动作在从句动作的发生的过程中或主从句两个动作同时发生。 ③由when引导的时间状语从句，主句用过去进行时，从句应用一般过去时；如果从句和主句的动作同时发生，两句都用过去进行时的时候，多用while引导，如： a. When the teacher came in, we were talking. 当此句改变主从句的位置时，则为： While we were talking, the teacher came in. b. They were singing while we were dancing. ④when和while 还可作并列连词。when表示“在那时”；while表示“而，却”，表对照关系。如： a. The children were running to move the bag of rice when they heard the sound of a motor bike. 孩子们正要跑过去搬开那袋米，这时他们听到了摩托车的声音。 b. He is strong while his brother is weak. 他长得很结实，而他弟弟却很瘦弱。 when; while 当……时候 while能用when代替; 但是when却不一定能用while代替. while+从句, 动作一定会延续 when+延续性动词/瞬间动词; when he arrived

When和While的区别(可编辑修改word版)

1、When 和While 的区别 when,while 都有“当……时候”的意思. when 既可表示某一点时间,也可以表示某一段时间. （一）在when 引导的时间状语从句中,其谓语动词可以是延续性的,也可以是非延续性的,可与主句中的谓语动词同时发生,也可在其后发生. 例如： 1、I was just reading a book when she came into my room. 她走进我房间时,我正在看书. （二）、while 只能表示某一段时间,不能表示某一点时间.在while 引导的时间状语从句中,其谓语动词只能是延续性的,而且也只能与主句中的谓语动词同时发生或存在. 例如： 1、While Jim was mending his bike, Lin Tao came to see him. 正当吉姆修自行车时,林涛来看他. Remark: 由when 引导的时间状语从句，主句用过去进行时，从句应用一般过去时；如果从句和主句的动作同时发生，两句都用过去进行时的时候，多用while 引导，如： a. When the teacher came in, we were talking. 2、倒装知识点 完全倒装 表示地点的副词here, there 置于句首, 且主语是名词(不是代词) 时 表示时间、方向的副词或介词短语置于句首, 且主语是名词(不是代词) 时 作表语的形容词、分词、介词短语、such 置于句首时 部分倒装 “ only+状语” 置于句首, 主句需要部分倒装 具有否定意义或半否定意义的副词以及含否定词的介词短语置于句首作状语时“so 或neither + 助动词/情态动词/be 动词+主语”表示“……也/也不” so/such...that...句型 以had/were/should 开头省略if 的虚拟条件句

过去进行时、when和while引导时间状语从句的区别

过去进行时 过去进行时表示过去某一时刻或者某段时间正在进行或发生的动作，常和表过去的时间状语连用，如： 1. I was doing my homework at this time yesterday. 昨天的这个时候我正在做作业。 2. They were waiting for you yesterday. 他们昨天一直在等你。 3. He was cooking in the kitchen at 12 o'clock yesterday. 昨天12点，他正在厨房烧饭。 过去进行时的构成： 肯定形式：主语+was/were+V-ing 否定形式：主语+was not (wasn't)/were not (weren't)+V-ing 疑问形式：Was/Were+主语+V-ing。 基本用法： 1. 过去进行时表示过去某一段时间或某一时刻正在进行的动作。常与之连用的时间状语有，at that time/moment, (at) this time yesterday (last night/Sunday/week…), at+点钟+yesterday (last night / Sunday…)，when sb. did sth.等时间状语从句，如： 1）What were you doing at 7p.m. yesterday? 昨天晚上七点你在干什么？ 2）I first met Mary three years ago. She was working at a radio shop at the time. 我第一次遇到玛丽是在三年前，当时她在一家无线电商店工作。 3）I was cooking when she knocked at the door. 她敲门时我正在做饭。 2. when后通常用表示暂短性动词，while后通常用表示持续性动词，而while所引导的状语从句中，谓语动词常用进行时态，如： When the car exploded I was walking past it. = While I was walking past the car it exploded. 3. when用作并列连词时，主句常用进行时态，从句则用一般过去时，表示主句动作发生的过程中，另一个意想不到的动作发生了。如： I was walking in the street when someone called me. 我正在街上走时突然有人喊我。 4. when作并列连词，表示“（这时）突然”之意时，第一个并列分句用过去进行时，when引导的并列分句用一般过去时。如： 1）I was taking a walk when I met him. 我正在散步，突然遇见了他。 2）We were playing outside when it began to rain. 我们正在外边玩，这时下起雨来了。 过去进行时和一般过去时的用法比较： 1）过去进行时表示过去正在进行的动作，而一般过去时则表示一个完整的动作。 例如：They were writing letters to their friends last night. 昨晚他们在写信给他们的朋友。（没有说明信是否写完） They wrote letters to their friends last night.

when和while的用法和区别

when和while的用法和区别 while和when都是表示同时，到底句子中是用when还是while主要看从句和主句中所使用的动词是短暂性动作（瞬时动词）还是持续性动作。 1、若主句表示的是一个短暂性的动作，而从句表示的是一个持续性动作时，两者都可用。如：He fell asleep when [while] he was reading. 他看书时睡着了。 I met him when [while] I was taking a walk in the park. 我在公园散步时遇到了他。 2、若主、从句表示两个同时进行的持续性动作，且强调主句表示的动作延续到从句所指的整个时间，通常要用while。如： Don’t talk while you’re eating. 吃饭时不要说话。 I kept silent while he was writing. 在他写的时候，我默不作声。 3、若从句是一个短暂性动作，而主句是一个持续性动作，可以when 但不用while。如：When he came in, I was listening to the radio. 他进来时，我在听收音机。 It was raining hard when we arrived. 我们到达时正下着大雨。 4、若主、从句表示的是两个同时(或几乎同时)发生的短暂性动作，一般要用when。如： I thought of it just when you opened your mouth. 就在你要说的时候，我也想到了。 至于什么是短暂性动作，什么是持续性动作，其实有个很简单的规律。就是如果是进行时态，一般是持续性的。如果是过去式，一般是短暂性动作。 对于，填写when还是while的问题，通常首先看主句和从句中的时态，再根据以上4个规律来判断填写那个单词。 When和While的区别 通常when 后面接一般过去时while 后面接过去进行时 ①when是at or during the time that, 既指时间点，也可指一段时间，while是during the time that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while从句中的动词必须是延续性动词。 ②when 说明从句的动作和主句的动作可以是同时，也可以是先后发生；while 则强调主句的动作在从句动作的发生的过程中或主从句两个动作同时发生。 ③由when引导的时间状语从句，主句用过去进行时，从句应用一般过去时；如果从句和主句的动作同时发生，两句都用过去进行时的时候，多用while引导，如： a. When the teacher came in, we were talking. 当此句改变主从句的位置时，则为： While we were talking, the teacher came in. b. They were singing while we were dancing. ④when和while 还可作并列连词。when表示“在那时”；while表示“而，却”，表对照关系。如： a. The children were running to move the bag of rice when they heard the sound of a motor bike.

(易错题精选)初中英语词汇辨析的难题汇编及解析

一、选择题 1．Is this a photo of your son? He looks________ in the blue T-shirt. A．lovely B．quietly C．beautiful D．happily 2．—Jerry looks so tired. He works too hard. —He has to ________ a family of four on his own. A．offer B．support C．provide D．remain 3．— Mr. Wilson, can I ask you some questions about your speech? — Certainly, feel __________ to ask me. A．good B．patient C．free D．happy 4．Some animals carry seeds from one place to another, ________ plants can spread to new places. A．so B．or C．but D．for 5．— Can you tell us about our new teacher? —Oh, I’m sorry. I know________ about him because I haven’t seen him before. A．something B．anything C．nothing D．everything 6．—Help yourselves! The drinks are ________ me. —Thank you. You’re always so generous. A．above B．in C．on D．over 7．Gina didn’t study medicine. ________, she decided to become an actor. A．Instead B．Again C．Anyway D．Also 8．—Have you got Kathy’s________ for her concert? —Yes, I’d like to go and enjoy it. A．interview B．information C．invitation D．introduction 9．More and more people have realized that clear waters and green mountains are as ________ as mountain of gold and silver. A．central B．harmful C．valuable D．careful 10．Kangkang usually does her homework ________ it is very late at night. A．until B．when C．before D．after 11．He ________all the “No Smoking” signs and lit up a cigarette. A．requested B．attacked C．protected D．ignored 12．一Where is Mr. Brown? 一I think he's _____________ the music hall. A．on B．in C．over D．from 13．— Is your home close to the school, Tom? — No, it's a long way, but I am________ late for school because I get up early daily. A．always B．usually C．never D．sometimes 14．—Mum, I don’t want the trousers. They’re too long.

when-的用法

when 的用法 一、when 用作副词。 1. 用作疑问副词，引导特殊疑问句。(什么时候，何时 [at what time ])例如： ①When will you come to see me? ②When are they going to visit the Great Wall? 2. 用作连接副词，通常用来引导名词性从句[主语从句、表语从句、同位语从句、宾语从句]及起名词作用的“when ＋动词不定式”结构。(什么时候，何时 [at which; on which ])例如： ①When he comes is not known. [主语从句] ②The morning is when I am busiest. [表语从句] ④I don't know when the plane takes off. [宾语从句] ⑤I don't know when to leave for London. [宾语] 3. 用作关系副词，引导限定性定语从句和非限定性定语从句。(在…的时候 [at/on/in/during which])例如： ①Do you still remember the days when we stayed in America? ②The day will come soon when the Chinese astronauts will go to the moon. ③It happened ten years ago, when I was a child. ④We will go to the countryside at the beginning of June, when the summer harvest will start. 二 . when 用作连词。 1. 用作从属连词，意为“当……的时候[at the time when ]”，引导时间状语从句。例如： ①They learned a lot from the peasants when they stayed in the village. ②It was snowing when he arrived at the station. 【点津】如果 when 引导的从句中的主语和主句中的主语一致，且从句中的谓语动词是“be ＋分词”或从句主语是 it ，则 be 动词及其主语常可省略。例如： ③When（ he was ）asked why he was late, he made no answer. ④I'll tell him about it when（ it is ）possible. 2. 用作从属连词，意为“一……就……”，引导时间状语从句。[immediately after]例如： ①We will stand up when the teacher comes into the classroom. 老师一进教室我们就起立。 ②Fire the rockets when I give the signal. 3. 用作从属连词，意为“还没 / 刚刚/刚一……就”，引导时间状语从句。[immediately after]例如： ①I had hardly opened the door when he came in. 我刚一开门，他就进来了。 ②I had not been reading for half an hour when I heard someone call my name. 【点津】hardly…when和no sooner…than的结构要注意三点：意思为“一A就B“；A句通常用完成时态；hardly 和 no sooner 位于句首时要注意部分倒装。 4. 用作从属连词，意为“倘若，如果”，表示条件。例如： ①Turn off the switch when anything goes wrong with the machine. 如果机器发生故障，就把电源关上。 ②He will be likely to recover when he is operated on. 5. 用作从属连词，意为“既然，尽管”，表示让步。例如： ①Why use metal when you can use plastic?既然能用塑料,为什么用金属? ②They kept trying when they knew it was hopeless. 尽管他们知道那件事没有希望，可是他们还在不断地努力。6. 用作并列连词，意为“在那时，届时;就在这时”，表示时间。这时主句中可以用过去进行时，过去完成时或“ was/were about to do sth. ”结构。 ①Last night I was about to go to bed when the phone rang. ②I was cooking in the kitchen when someone knocked at the door. ③He had just finished the book when supper was served. 7. 用作并列连词，意为“虽然、然而、可是”，表示转折。例如： ①He usually walks to work when he might take a bus. 虽然他可 以坐公共汽车上班，但他却常常步行上班。 ②I had only twenty dollars when I needed thirty to buy the dictionary.我需要 30 美元买那本字典，可是我只有20美元。 8. 用作并列连词，意为“而、却”，表示对比。例如： How can he say that everything is fine when it's obvious that it is not? 他怎能说一切都好呢？情况显然不是那样。 三 . when 用作代词[which time]。 when 作为代词常常位于介词之后，意为“那时，什么时候”。例如： ①Since when have you been studying Japanese? 【点津】since when 作引导词时是“介词（since）+关系代词（when）”的结构，when意为which time。since when常引导非限制性定语从句，从句应用完成时态。 ②I came here in 1949, since when I have been engaged in this work. 我1949年到这里，从那时起我就担任这项工作。 ③We came back on Tuesday, since when we have been working in the repair shop. ④We came a week ago, since when the weather has been bad. 四、when 还可用作名词，前面常常用定冠词 the。 the when 表示事 件发生的时间,常常与 the where, the how 并列使用。 He told the police the when and the how of the accident. 他告 诉警察事故发生的时间及发生的原委。 ［巩固练习］ 1. I remember ______ this used to be a quiet village. A. when B. how C. where D. what 2. Why do you want a new job _____ you've got such a good one already? A. that B. where C. which D. when 3. It was an exciting moment for these football fans this year, ______ for the first time in years their team won the World Cup. A. that B. while C. which D. when 4. We are living in an age _______ many things are done on computer. A. which B. that C. where D. when 5. The reporter said that the UFO ______ east to west when he saw it. A. was travelling B. travelled C. had been travelling D. was to travel 6. ______ got into the room _________ the telephone rang. A. He hardly had; then B. Hardly had he; when C. He had not; than D. Not had he; when 7. ---- Can I join your club, Dad? ---- You can when you _______ a bit older. A. get B. will got C. are getting D. will have got 8. I shall never forget those days ________ I lived in the countryside with the farmers, ________ had a great effect on my life. A. that; which B. when; which C. which; that D. when; who 9. The film brought the hours back to me ______ I was taken good care of in that faraway village. A. until B. that C. when D. where 10. He was about to tell me the secret ______ someone patted him on the shoulder.