四级作文：环境污染

四级作文：环境污染（精选8篇）

1.四级作文：环境污染 篇一

What Can We Do for the Environment

Hello, everyone. I’m Li Hua. It’s nice to speak about what we can do for the environment, and I think each of us can do a little bit to help with this problem.

The first thing we can do is to use cloth bags in stead of plastic bags when we go shopping. It helps to protect the environment. The second thing we can do is to reuse(再利用) the old textbooks as possible as we can. We should also never forget to turn off the lights when we leave the classrooms in order to save energy.What’s more, it would be better if we walk or ride a bike to school. We should try our best to reduce pollution and waste.

In fact, even the simplest everyday activities(日常活动) can make a real difference to(对…有影响) the environment. I believe we can make the world a better place to live in.

Thank you for your listening!

2.四级作文：环境污染 篇二

关键词：氨基甲酸酯农药,液相色谱-三重四级杆质谱,固相萃取

1 引言

氨基甲酸酯类农药是继有机磷、有机氯之后出现的又一类重要杀虫剂, 因具有作用迅速、易分解、残留毒性小等优点而被全球广泛使用。但其水溶性较高, 很容易通过地表径流、大气干湿沉降等途径对地表水、地下水等饮用水源造成污染, 威胁人类的身体健康。环境水体中的氨基甲酸酯农药污染已引起了全球范围的广泛关注, 各国纷纷制定地表水及集中式生活饮用水源的氨基甲酸酯农药控制标准, 我国的地表水环境质量标准 (GB3838-2002) 中也规定了某些氨基甲酸酯农药 (如甲萘威等) 的标准限值[1~3]。

本实验采用固相萃取法测定水样中的氨基甲酸酯类农药残留。在优化质谱检测参数时, 本实验采取了质谱多反应监测 (Multiple Reaction Monitoring, MRM) 技术。这是一种基于已知信息或假定信息有针对性地获取数据, 进行质谱信号采集的技术。具有特异性强、灵敏度高、准确度高、重现性好、线性动态范围宽、自动化高通量的突出优点, 这些特质能够满足目前很多研究领域的迫切需要。

MRM技术的原理是一种基于已知或假定的反应离子信息, 有针对性地选择数据进行质谱信号采集, 对符合规则的离子进行信号记录, 去除不符合规则离子信号的干扰, 通过对数据的统计分析从而获取质谱定量信息的质谱技术。MRM技术是在单反应监测 (Single Reaction Monitoring, SRM) 技术的基础上演化而来的。对于MRM技术而言关键在于首先要能够检测到具有特异性的母离子, 然后将选定的特异性母离子进行碰撞诱导 (collision-induced) , 最后去除其他子离子的干扰, 只对选定的特异子离子进行质谱信号的采集。由于三重四级杆质谱 (Triple Quadrupole System, TQS) 是进行单一质荷比扫描最灵敏的质谱系统, 因此是最适合MRM分析的质谱仪器。

2 试剂和材料

标准物质:氨基甲酸酯混合标液, 闭光冷藏保存。内含五种氨基甲酸酯类化合物, 灭多威、涕灭威、克百威、甲萘威与异丙威。乙腈:农残级或相似级别。超纯水, 自制。标准使用溶液:分别准确移取250μL氨基甲酸酯类标准溶液 (2.1) 于10mL容量瓶中, 配制成混合标准中间液, 在冰箱4℃条件下可保存半年。标准系列溶液:根据检测器灵敏度、线性要求以及待测试样中氨基甲酸酯类化合物浓度, 配制成标准系列溶液。在4℃条件下避光保存, 有效期2个月。

3 仪器和设备

液相色谱/质谱仪:安捷伦公司6460, 具电喷雾电离源 (ESI) 、三重四级杆结构 (QQQ) 和化学工作站。色谱柱:安捷伦公司SB-C18, 2.1mm×50mm, 1.80 m;氮气超纯钢瓶气:纯度99.999%。容量瓶:25mL、10mL。微量注射器:5L、50L、100L。样品瓶:2mL。安捷伦12位手动固相萃取仪。Waters公司HLB固相萃取小柱 (乙烯吡咯烷酮/二乙烯苯聚合物, 500mg, 6mL) 。

4 试验步骤及条件摸索

4.1 色谱分析条件优化

在仪器维修、开关机、挪动或质量数漂移时需要进行调谐, 本实验采用MRM方式定量分析目标污染物, 选用ESI+检测目标物, 优化各条件如下:

毛细管电压:300kV;电离源温度:300℃;氮气流量:10L/min;色谱柱:SB-C18, 2.1 50mm, 1.80m;柱温箱:30℃;进样量:5μL;流动相:在传统液相色谱/质谱联用的分析方法中, 通常需在流动相中加入适当的有机酸或缓冲盐来增强目标物的离子化效率, 进而增强分析方法的灵敏度。A相为添加了0.1%甲酸溶液的纯水, B相为纯乙腈, 流速0.3mL/min;梯度:如表1所示, 5种氨基甲酸酯类化合物在7min内即可出峰完毕。

4.2 质谱条件优化

进样浓度1μg/mL的标准溶液进行质谱条件优化, 确定各目标物合适的最佳碰撞电压、定量离子对, MRM模式下优化后的条件如表2所示。

4.3 固相萃取法测定水样中的氨基甲酸酯类农药

本实验采用固相萃取法测定水样中的氨基甲酸酯类农药残留。固相萃取 (Solid-Phase Extraction, 简称SPE) 是近年发展起来的一种样品预处理技术, 由液固萃取和液相色谱技术相结合发展而来, 主要用于样品的分离、纯化和浓缩。由于具有回收率和富集倍数高、有机溶剂用量少、对环境友好、无相分离操作、易于收集级分、能处理小体积试样、操作简单和易于实现自动化等优点, 目前已成为最常用的样品前处理方法之一, 并被广泛应用与各个领域。

SPE是利用选择性吸附与选择性洗脱的液相色谱法分离原理。较常用的方法是使液体样品通过一吸附剂, 保留其中被测物质, 再选用适当强度溶剂冲去杂质, 然后用少量溶剂洗脱被测物质, 从而达到快速分离净化与浓缩的目的。也可选择性吸附干扰杂质, 而让被测物质流出;或同时吸附杂质和被测物质, 再使用合适的溶剂选择性洗脱被测物质。其实现过程主要包括以下步骤:首先, 一个样品包括分离物和干扰物通过吸附剂;其次, 吸附剂选择性的保留分离物和一些干扰物, 其他干扰物通过吸附剂;然后, 用适当的溶剂淋洗吸附剂, 使先前保留的干扰物选择性的淋洗掉, 分离物保留在吸附剂床上;最后, 纯化、浓缩的分离物从吸附剂上淋洗下来。

实验分别用10mL甲醇、乙腈、水活化固相萃取小柱, 流量为5mL/min。水样上样速度为4mL/min, 上样量为100mL, 10%甲醇淋洗, 氮气吹干15min, 5mL溶剂洗脱两次, 氮吹仪浓缩至近干, 甲醇:水 (V∶V=1∶1) 定容至1mL, 过滤后进样仪器分析。对于悬浮颗粒物较高的水样, 可使用多根固相萃取小柱对样品进行富集净化, 合并洗脱液后用氮吹仪浓缩、过滤、进样仪器分析。

5 结果分析

5.1 定性结果

根据质谱图中各组分的特征碎片, 确定被测试样中出现的组分的数目和组分名称。

5.2 定量结果

定量方法为外标标准曲线法定量。其各自标准曲线如表3所示。

6 结语

本实验采用固相萃取 (SPE) 技术, 对水样中5种氨基甲酸酯类农药进行提取、净化、浓缩前处理, 优选了固相萃取小柱填料及洗脱条件, 优化了高效液相/质谱仪器参数, 建立水样中痕量氨基甲酸酯农药的SPE-LC/MS分析方法。

该方法在7min之内完成5种目标物的分析, 加标回收率为91.5%~101%, 相对标准偏差为3.2%~9.2%, 检测限为0.010~0.092μg/L。该方法具有简便、快捷、准确、灵敏的特点, 对环境水体的污染现状调查工作与对农药污染的应急检测具有实际应用价值。

参考文献

[1]刘潇威, 李凌云, 吕俊岗, 等.高效液相色谱法测定粮食中氨基甲酸酯类杀虫剂及其代谢物残留量[J].分析试验室, 2007, 26 (4) :111~113.

[2]王德海, 谭伟, 吴晓波, 等.混合粉剂扑草净和乙草胺的反相高效液相色谱分析[J].云南民族大学学报:自然科学版, 2010, 19 (3) :198~200.

3.英语四级作文写作技巧 篇三

自2007年6月起，英语新四级考试在全国范围内展开。第一部分是写作，测试学生用英语进行书面表达的能力，所占分值比例为15%，求考生根据规定的题目和提供的提纲、情景、或图表等在30分钟内写完至少120个单词的文章。出题的方式和涉及的话题越来越与学生的真实生活接近，越来越强调实用性，而且常常和当时社会发生的事情联系在一起。写作要求是：思想表达准确，意义连贯，无严重语法错误。

2.四级作文写作技巧

A.审题布局，理清结构

拿到作文考题，先要仔细分析作文题目，不是直接开写。要写出一篇相对成功的文章，要树立一个框架意识，各段的安排必须合理，否则即使语言运用得再好，也很难得高分。一般来说，四级作文都是由三个段落组成，有时也可以是四段，其结构和内容必须根据文章主题和提纲中给出的段落提示来确定，不能随意安排。以2012年6月的作文为例：

Directions： For this part， you are allowed 30 minutes to write a short essay entitled On Excessive Packaging following the outline given below. You should write at least 120 words but no more than 180 words.

目前许多商品存在过度包装的现象，出现这一现象的原因，我对这一现象的看法和建议。

分析标题和提纲可知，本文应该是说明与议论相结合。根据提纲，写作时指出目前许多商品存在过度包装的现象，并说明该现象的典型表现；然后分析出现这一现象的原因；最后发表我对这一现象的看法和建议。

据此，文章分为三段，开头段交待全文主题：目前许多商品存在过度包装现象；中间段围绕出现这一现象的原因进行论述；结尾段提出我对这一现象的看法和建议。这三部分缺一不可。这样段落层次分明，构架清晰合理，要完成一篇文章结构完整的四级作文便不难了。

此外，每个段落的结构也要求具有完整性。一个段落必须有若干个扩展句，使主题思想得到充分展开。如果只有主题句而没有扩展句来进一步说明和阐述主题，就不能构成一个完整的段落。

全篇各个段落都要为一个中心思想服务，而且每个段落都要围绕一个主题句来展开，如果有游离于中心思想之外的段落或句子则会使文章零散杂乱。另外，句子的结构杂乱也会造成段落松散，从而导致文章主题不明确，令读者不知所云。

B.突出主题、句式多变

长句短句错落有致。真正优秀的文章应做到长短句搭配合理，难简结合，平实中见功力。很多考生缺乏写作训练，往往在作文中忽视运用长句或是长句运用不当，因此在平时训练时，考生就应该有意识地在每段中都设置出1至2个有特色的长句，如并列句、排比句、主从复合句等，使文章错落有致、行文流畅并体现出语言功底。

主动被动合理运用。按照汉语的写作思维，我们习惯于表现动作的执行者，但当把我们这种思维应用于英语写作时，就会出现一个明显的缺陷，因为英语的native speakers在写作过程中更注重表现事情本身，所以在他们的文章里，使用被动语态或者不体现动作执行者的句子更多一些。当然，在写作过程中，并不是要一味地追求被动语态的使用，在什么情

况下用主动，什么情况下用被动，这与陈述对象有密切的关系，英语写作中强调叙述对象的一致性，所以在实际写作中，一定要合理运用主动和被动。

倒装、强调适当穿插。强调句式是一种突出重点的有效旬式。另外，倒装句式也常用于达到强调的目的。因此，在写作中适当穿插使用强调句和倒装句，不仅可以突出强调重点部分，而且能够丰富句式，起到修饰作用，达到意想不到的表达效果。

比较结构巧妙使用。比较结构是英语中使用频率较高的一种句式，如果能够恰当地运用，可以使语言表达更加地道，对各种类型作文的写作都大有裨益。

句与句间衔接紧密。英语中十分重视句与句之间的形合，在写作中即使上下旬之间的意义联系紧密，逻辑关系很明显，也不能省略连接词或过渡词，否则就不符合英语的思维与表达习惯。恰当地使用连接词，尤其是表示从属关系的连接词（如who，Which，that，because，since，although，if，unless，as等），不仅能丰富句型，而且能将意思表达得更加清楚，使句与句之间衔接更加紧密，意义更加连贯。

C.出现亮点

遣词用语准确地道。词语的选用直接关系到句子的优劣，也势必关系到段落主体思想的表达，进而关系到整篇文章的质量，所以“把恰当的词用到恰当的地方”成为写作的至理名言。在写作中选择准确的词汇、使用地道的语言，不仅可以使文章的表达更加到位，更重要的是能起到“点睛”的作用，成为作文获得高分的亮点之一。

开头结尾突破常规。文章开头段除了要表明主题外，还有一个重要的任务就是要引起读者的兴趣，使文章具有与众不同的吸引力。四级写作阅卷往往是根据第一段确定文章的分数档次，如果能在开头就表现出不同凡响的语句，对于提高整个文章的分数档次会有很大的作用。

另外，文章的结尾也同样不容忽视。结尾篇幅虽然不宜过长，但却也是决定文章成败的点睛之笔，因此可以有意识地采取某种突破常规的写作手法，让考官在读到结尾时能眼睛一亮。

适当应用修辞手法。准确恰当地使用修辞手法，会极大地增强文章的表现力，使文章更加生动形象、意蕴丰富并且引人人胜。英文写作中常见的修辞手法有比喻、平行结构、修辞问句等。

恰当使用警句格言。一篇好的作文在有了合理的结构和布局之外，如果能有一定的文采，会锦上添花，而体现文采的一个重要手段就是恰当地使用警句格言。

【例】 As an old Chinese saying goes，traveling ten thousand miles and reading ten thousand books is the top ideal for people. Travel does broaden our mind. It enables us to appreciate beautiful scenery，value the culture and customs of the country visited and learn its history.

3.结语

4.四级作文：环境污染 篇四

(1)the world we live in is becoming more and more intolerable because of environmental destruction.

(2)a lot of measures have been taken …

(3)however, the problem of environmental protection remains far from being solved.

the world we live in is becoming more and more intolerable because of environmental destruction. for example , forest destruction results in decrease of planting land and unpleasant weather. in addition, man is faced with problems of water pollution and air pollution.

a lot of measures have been taken. planting trees helps improve and beautify the environment. besides, laws concerning environmental protection have been put into effect and achieved good results.

however, the problem of environmental protection remains far from being solved. on the one hand, the environment pollution and destruction are getting worse and worse in the modern world. on the other hand, the lack of knowledge about the importance of protecting environment hinders the solving of the problem. in a word, there is a long way to go before we enjoy a clean and comfortable world.

★ 四级模板

★ 四级范文

★ 四级作文

★ 四级作文模版

★ 四级万能作文模板

★ 四级写作

★ 四级万能作文

★ 英语四级范文

★ 四级经验

5.12月英语四级翻译模拟空气污染 篇五

2018年12月英语四级翻译模拟:空气污染

请将下面这段话翻译成英文：

随着世界人口越来越密集（densely populated),空气污染已经成了严重的问题。空气污染主要来源于四个主要的人类活动领域：工业、能源业、交通运输业以及农业。经营工厂,为火车、飞机和公共汽车提供动力都需要能源。几乎所有这些能源都是通过燃烧燃料产生的,这就会造成空气污染。科学家们正在研究能减少环境破坏的新发电方式。增强的公共环保意识使诸如回收利用(recycling)等活动产生。参考译文：

6.四级作文：环境污染 篇六

大学英语四级作文套句总结

开头

Recently, the problem of … has aroused people’s concern.最近,…问题已引起人们的关注.Internet has been playing an increasingly important role in our day-to-day life.It has brought a lot of benefits but has created some serious problems as well.互联网已在我们的生活中扮演着越来越重要的角色.它给我们带来了许多好处,但也产生了一些严重的问题.Nowadays,(overpopulation)has become a problem we have to face.如今,(人口过剩)已成为我们不得不面对的问题了.It is commonly believed that… / It is a common belief that…

人们一般认为…

Many people insist that…

很多人坚持认为…

With the development of science and technology, more and more people believe that … 随着科技的发展,越来越多的人认为…

A lot of people seem to think that…

很多人似乎认为… 结尾

Taking all these factors into consideration, we naturally come to the conclusion that…

把所有这些因素加以考虑,我们自然会得出结论…

Taking into account all these factors, we may reasonably come to the conclusion that … 考虑所有这些因素, 我们可能会得出合理的结论…

Hence/Therefore, we’d better come to the conclusion that…

因此,我们最好得出这样的结论…

There is no doubt that(job-hopping)has its drawbacks as well as merits.毫无疑问,跳槽有优点也有缺点.All in all, we cannot live without… But at the same time we must try to find out new ways to cope with the problems that would arise.总之,我们没有…是无法生活的.但同时,我们必须寻求新的解决办法来对付可能出现的新问题.引出不同观点:

People’s views on… vary from person to person.Some hold that….However, others believe that….人们对…的观点因人而异.有些人认为…..然而其他人却认为．．．

People may have different opinions on…

人们对…可能会有不同的见解.Attitudes towards(drugs)vary from person to person.人们对待吸毒的态度因人而异.There are different opinions among people as to…

关于….人们的观点大不相同.Different people hold different attitudes toward(failure).对(失败)人们的态度各不相同.提出建议:

It is high time that we put an end to the(trend).该是我们停止这一趋势的时候了.It is time to take the advice of … and to put special emphasis on the improvement of …

该是采纳…的建议,并对…的进展给予特殊重视的时候了.1

作文专项：（学生版）

There is no doubt that enough concern must be paid to the problem of …

毫无疑问,对…问题应予以足够的重视.Obviously,….If we want to do something… , it is essential that…

显然,如果我们想做某事,很重要的是…

Only in this way can we… 只有这样,我们才能…

It must be realized that… 我们必须意识到… 预示后果:

Obviously, if we don’t control the problem, the chances are that… will lead us in danger.很明显,如果我们不能控制这一问题,很有可能我们会陷入危险.No doubt, unless we take effective measures, it is very likely that…

毫无疑问,除非我们采取有效措施,很可能会…

It is urgent that immediate measures should be taken to stop the situation.很紧迫的是,应立即采取措施阻止这一事态的发展.论证

From my point of view, it is more reasonable to support the first opinion rather than the second.在我看来,支持第一种观点比支持第二种观点更有道理.I cannot entirely agree with the idea that… 我无法完全同意这一观点….Personally, I am standing on the side of …就个人而言, 我站在…的一边.I sincerely believe that… 我真诚地相信…

In my opinion, it is more advisable to do … than to do….在我个人看来,做…比做…更明智.Finally, to speak frankly, there is also a more practical reason why… 给出原因:

This phenomenon exists for a number of reasons.First, … Second, … Third, …

这一现象的存在是有许多原因的.首先, … 第二, … 第三,…

Why did… ? For one thing… For another….Perhaps the primary reason is…

为什么会…? 一个原因是… 令一个原因是…或许其主要原因是….I quite agree with the statement that… the reasons are chiefly as follows.我十分赞同这一论述,即…,其主要原因如下: 列出解决办法:

Here are some suggestions for handling…

这是如何处理某事的一些建议.The best way to solve the troubles is…

解决这些麻烦的最好办法是…

People have figured out many ways to solve this problem.人们已找出许多办法来解决这个问题.批判错误观点和做法:

As far as something is concerned, ….就某事而言,…

It was obvious that… 很显然,….It may be true that…, but it doesn’t mean that…

可能…是对的,但这并不意味着…

It is natural to believe that… , but we shouldn’t ignore that…

认为….是很自然的,但我们不应忽视….There is no evidence to suggest that… 没有证据表明…

作文专项：（学生版）

过渡词

强调still, Indeed, apparently, oddly enough, of course, after all, significantly, interestingly, also, above all, surely, certainly, undoubtedly, in any case, anyway, above all, in fact, especially, obviously, clearly.比较like, similarly, likewise, in the same way, in the same manner, equally.对比by contrast, on the contrary, while, whereas, on the other hand, unlike, instead, but, conversely, different from, however, nevertheless, otherwise, whereas, unlike, yet, in contrast.列举for example, for instance, such as, take …for example.Except(for), to illustrate.时间later, next, then, finally, at last, eventually, meanwhile, from now on, at the same time, for the time being, in the end, immediately, in the meantime, in the meanwhile, recently, soon, now and then, during, nowadays, since, lately, as soon as, afterwards, temporarily, earlier, now, after a while.顺序first, second, third, then, finally, to begin with, first of all, in the first place, last, next, above all, last but not the least, first and most important.可能presumably, probably, perhaps.解释 in other words, in fact, as a matter of fact, that is, namely, in simpler terms.递进What is more, in addition, and, besides, also, furthermore, too, moreover, furthermore, as well as, additionally, again.让步although, after all, in spite of…, despite, even if, even though, though, admittedly, whatever may happen.转折 however, rather than, instead of, but, yet, on the other hand, unfortunately.whereas 原因 for this reason, due to, thanks to, because, because of, as, since, owing to.结果as a result, thus, hence, so, therefore, accordingly, consequently, as consequence.总结on the whole, in conclusion, in a word, to sum up, in brief, in summary, to conclude, to summarize, in short.其他 Mostly, occasionally, currently, naturally, mainly, exactly, evidently, frankly, commonly, for this purpose, to a large extent, for most of us, in many cases, in this case 图表作文常用句型

As is shown in the graph… 如图所示…

The graph shows that… 图表显示…

As can be seen from the table, … 从表格中可以看出…

From the chart, we know that… 从这张表中,我们可知…

All these data clearly prove the fact that…

所有这些数据明显证明这一事实,即…

The increase of ….in the city has reached to 20%.这个城市的….增长已达到20%.In 1985, the number remained the same.1985年,这个数字保持不变.There was a gradual decline in 1989.1989年,出现了逐渐下降的情况.汇总：开头段常用核心句型

The arguer may be right about…, but he seems to neglect to mention the fact that… Contrary to generally accepted views, I argue that… It is true that…, but this is not to say that…

The main/obvious problem with this argument is that it is blind to the basic fact that… It would be natural/reasonable to think that…, but it would be absurd to claim that…

作文专项：（学生版）

There is absolutely no reason for us to believe that…

At first thought, it may seem an attractive idea, but on second thought, we find that… The problem/fact is that…

As far as I am concerned, I believe that…

Those who object to…argue that…But people who favor…, on the other hand, argue that… 中间段的常用核心句型

The change in…mainly results from… The increase in…is due to the fact that… Many people would claim that… One of the reasons given for is that…

There are a variety of reasons for this dramatic growth in… First… Second… FinallyWhy are(is/do/did)…? For one thing… For another… History is filled with the examples of… As is shown in the table released by the government, it can be learned that… There is(no)good evidence to…

We must admit the undeniable fact that… No one can deny the fact that…

Experience(Evidence)suggests that… The same is true of… 结尾段的常用核心句型

It is high time that we placed great emphasis on the improvement of…

It is high time that we put an end to the unhealthy situation(tendency/phenomenon)ofThere is no easy solution to the problem of…, but… might be useful.Unless there is a common realization of…, it is very likely that…

It is essential that effective measures should be taken to prevent the situation.It is suggested that great efforts should be made to control the growth of…

It is hoped that great efforts should be focused on finding(developing/improving)… Anyway, more publicity should be given to the potential effects of…

7.四级作文：环境污染 篇七

一、打好写作基础

1. 指导学生掌握科学记忆单词的方法，扩大学生的词汇量。

单词是构成一篇文章的最基本要素。要写出一篇内容充实的文章，就必须掌握足够的词汇，否则“巧妇难为无米之炊”，即使有再好的灵感和思路也无法表达出来。单词的记忆方法因人而异，在很大程度上靠学习者的勤奋刻苦、持之以恒，不过，在学生记忆单词的过程中，教师若能进行正确有效的引导，往往就能达到事半功倍的效果。例如，教师可以引导学生采用扩展、派生和比较记忆等方法记单词。如学习“complaint”，应同时记忆其动词形式“complain”;学习“superior”，可同时记忆其反义词“inferior”;学习“pose”，要将它的形近词“impose”和“expose”一起进行对比记忆。这样，学生在使用词语时，不仅不会将词语的词性及一些形近、义近词混淆，反而达到了扩大词汇量的目的。

2. 要求学生认真严谨地写好每一个句子。

如果说词汇是一颗颗珍珠的话，那么句子是通过语法这根线串起来的一串珍珠项链。对于大多数的学生来说，他们所掌握的英语语法知识完全足以写出完整通顺的句子和段落，但在批改学生的作文时，笔者发现，有些学生写的文章读起来给人一种支离破碎的感觉。其原因在于在一篇作文中，这些学生所写的句子存在很多语法错误。因此，在平时的写作训练中，教师应要求学生以认真严谨的态度写每一个句子，同时进行语法的自我检查，也就是说，写作时，学生应提醒自己注意句子中的主谓一致，冠词的使用，单复数形式，以及句子应使用的时态和语态等。只有写好每一句话，才能写出一篇流利通顺的文章。

3. 让学生学会用简单的语言表达自己的意思和用不同的句子表达同一个意思。

笔者发现，在平时的写作训练中，有的学生不使用学过的比较简单常用的词语，却喜欢借助电子词典，用拼写复杂、比较少用的单词写，久而久之便形成了对电子词典的依赖性。一旦没了电子词典，学生就会感觉失去依靠，产生一定程度的紧张心理，从而影响了写作水平的发挥。另外，在英语写作中，同一个意思很多情况下可有不同的表达。因此，在写作训练中，教师应要求学生学会将一个意思用不同的句型或方式表达出来。这样可以使学生的表达更趋灵活，在遇到难以表达自己的想法或者对表达准确性不够肯定时，学生自己也能自然而然地尝试换另一种方式表达，避免钻进“死胡同”。

二、强化写作训练

1. 要求学生多思考、勤练笔。

一个学期仅仅写三到四篇作文是无法达到训练写作的目的的。写作课的主要任务是“督促学生写，保持写作的频率”[2]。因此，教师除了定期给学生布置写作任务外，平时还可要求学生记下自己生活中的所见所闻、所感所思。比如写写电影观后感、班级院系的活动、自己的同学朋友和学习计划等。此外，教师还可充分利用网络资源，要求学生就热门话题展开讨论。学生可以畅所欲言，不必担心语法错误，以此达到练笔的目的。

2. 让学生养成良好的写作习惯。

据笔者了解，在四级考试中，部分学生无法在规定的30分钟内按照要求写出不少于120字的作文。原因之一在于这些学生在平时的课外作文训练中，拖拖拉拉，没有给自己设定时间。这样，一到考试，他们就很难转变写作习惯，因而无法很好地完成作文。可见，养成良好的写作习惯是十分必要的。因此，如果课时充足，教师就可要求学生在课堂上完成作文;而如果是在课后完成作文，教师就可要求学生养成在一定的时间内完成一篇作文的习惯。

三、改进批改方法

作文的批改和点评环节十分重要。对作文的批改和点评，可以让学生清楚地认识自身的写作能力，从而不断改进，提高写作水平。由于大学英语科各班学生人数一般较多，如果每次都把学生写的作文全部交由教师批改，一则批改效果不佳，另外教师的工作负担也很重。笔者认为，除了批改学生的作文这一方式外，教师还可运用互评法完成作文的批改。“互评法(peer revision)是批改学生作文的一种方式，即学生们相互阅读和批改彼此的作文。”[3]具体操作可按照“Claudia L.Keh (1990)提出的七步走：输入、初稿、同学评估、第二稿、写作小组、教师和学生讨论、定稿。”[4]教师可以将学生分成几个小组，让小组成员对该组同学的作文进行分析、讨论、修改和评注，教师适时地进行必要的指导和答疑并最终定稿。采用这种模式不仅调动了学生学习的积极性和主动性，促进了学生之间的交流学习，而且使学生对错误有了更清晰的认识，避免再犯同样或类似的错误。

写文章就是构建一座文字的建筑，只有夯实基础，强化训练，才能写出构架清晰、内容充实的精彩之作。学习任何语言都应以应用为目的，提高学生的写作水平，提高学生应用英语的能力，需要师生共同努力。

参考文献

[1]http://baike.baidu.com/view/1705577.htm.

[2]黄源深.好文章是“写”出来的[J].外语界, 2006 (5) :13.

[3]丁士英.同学间互评与英语写作[J].职业时空, 2008 (05) :59.

8.四级作文预测 篇八

Directions: For this part, you are allowed 30 minutes to write a composition on the topic Reserving a Seat.You should write at least 120 words, and base your composition on the outline(given in Chinese)below:

1)很多大学里“占座”现象十分普遍

2)这种现象会带来哪些影响

3)你 对此的看法

【思路点拨】

本题属于提纲式文字命题。提纲第1点指 出一种现象，提纲第2点要求分析该现象带来的影响，提纲第3点要 求谈谈“我”对该现象的看法。

根据所给提纲，本文应包含如下内容：描述大学生在教室和图书馆“占座”的现象;说明这种现象带来的 不良影响;阐述“我”对“占座”现象的看法。

Reserving a Seat

We often see there is a table cloth, a book or something else on the desk in the classroom or library, indicating the seat is taken.This kind of phenomenon is very usual in almost all colleges and universities.Strangely enough, most of students seem to take this for granted, and few will protest it.Though most of students’ taking seats in advance is for better study, this kind of phenomenon has great negative effects.On the one hand, it is a selfish behavior, which damages other students’ interests.Sometimes even if many students come to the classroom very early, they can not find a seat.On the other hand, reserving a seat violates the rule of fairness.No matter how late you come to class, the seat is still reserved for you even though many others are eager for that seat.Considering the above-mentioned, I think, it is high time that we college students took a good look of our behavior.Indeed, only if all of us can improve our consciousness, it is not a difficult task for us to get rid of this kind of phenomenon “reserving a seat”.流行病

Directions: For this part, you are allowed 30 minutes to write a composition on the topic Epidemics.You should write at least 120 words, and base your composition on the outline(given in Chinese)below:

1)流行病在我们的生活中随处可见

2)流行病会带来哪些危害

3)对此我们应采取哪些措施

Epidemics

Epidemics are rampant throughout the whole human history, and they have caused the most devastating impacts on us.Each year, numerous epidemics break out on earth and they have such characteristics as fast spreading and infectious.Epidemics are harmful in many ways.For one thing, it will make people and animals seriously ill or dead, which is a great loss to the country.For example, the outbreak of SARS once killed lots of people and brought great economic loss to the whole country.For another, there is no cure for many kinds of epidemic diseases.Once we are infected by one of them, it is difficult to be cured.To avoid the outbreak of some kind of epidemics as possible as we can, we should first change some unhealthy habits or customs.For example, meals served individually should be encouraged, which would reduce the possibility of the spread of germs.On the other hand, the government should learn how to deal with emergencies when an epidemic broke out.I believe as long as we treat and prevent epidemics in the right way, we will finally conquer them.新东方：2011年12月英语四级作文预测4篇(1)

一、Computers in Students’ Dorms

1).现在大学生宿舍几乎人手一台电脑

2).有些人认为会促进学生的学习，有些人认为会影响学生的学习

3).你的看法

首段现象描述：

On many dorms, it has become a prevalent phenomenon for one college student to possess a PC or a notebook.Meanwhile, a host of parents or teachers encourage and advocate college students to use computers in their life and study.Taking a look around, we can find a great many students and dorms like this.利弊分析(支持方观点+反方观点)

A number of individuals prefer or favor the phenomenon “One student, One PC”.In their eyes, studying with the help of computers will enhance students’ over-all development and competitiveness, because rich information on the Internet will enrich their knowledge and broaden their horizons.Even so, others hold a different view that using computers may carry some risks.First, buying PC calls for plenty of money;however, the quality of learning is not always as satisfactory as expected.Then, what worries many teachers is that students’ academic learning may be affected negatively by a variety of computer games.我的看法(或建议)

By and large, I am convinced that the advantages derived from the popularity of computers far outweigh the disadvantages.Without this machine, it is impossible for students to have more opportunities to acquire the knowledge beyond their campuses.Therefore, students are advisable to use the PC in a sensible way.新东方：2011年12月英语四级作文预测4篇(2)

二、Oversea Study at an Early Age

1.很多低龄学生出国留学

2.低龄学生出国留学的利弊

3.我的看法

首段现象描述：

In contemporary society, it has become a prevalent phenomenon for young students to pursue their oversea study at an early age.Meanwhile, a host of parents or teachers encourage and advocate their kids to prepare from primary school.Taking a look around, we can find a great many parents and children like this.利弊分析(支持方观点+方法观点)

A number of individuals prefer or favor studying abroad at an early age.In their eyes, this new experience will enhance students’ over-all development and competitiveness, because advanced education in developed nations will enrich their knowledge and broaden their horizons.Even so, others hold a different view that this practice may carry some risks.First, studying abroad as children calls for plenty of money;however, the quality of learning is not always as satisfactory as expected.Then, what worries many teachers is that students’ Chinese culture learning may be affected negatively by their living environment in foreign nations.我的看法(或建议)

By and large, I am convinced that the advantages derived from this phenomenon far outweigh the disadvantages.Without this experience, it is impossible for students to have more opportunities to acquire the knowledge beyond their nations.However, students are advisable to put the same emphasis on Chinese learning and oversea studying.新东方：2011年12月英语四级作文预测4篇(3)

三、Campaign for Student Leaders

1.很多大学生参加竞选学生干部

2.对此，人们看法不一

3.我的看法

首段现象描述：

On many campuses, it has become a prevalent phenomenon for college students to participate in the campaigns for student-leaders.Meanwhile, a host of parents or teachers encourage and advocate college students to take these chances to gain a favorable position in job-hunting.Taking a look around, we can find a great many students like this.利弊分析(支持方观点+方法观点)

A number of individuals prefer or favor students’ participation in associations as leaders.In their eyes, these wide opportunities will enhance students’ over-all development and competitiveness, because various activities will enrich their knowledge and broaden their horizons.Even so, others hold a different view that this campaign may carry some risks.First, preparing and participation calls for plenty of time, energy, even money;however, the result of campaign is not always as satisfactory as expected.Then, what worries many teachers is that students’ academic learning may be affected negatively by too many extra-curriculum activities in associations.我的看法(或建议)

By and large, I am convinced that the advantages derived from this activity far outweigh the disadvantages.Without it, it is impossible for students to have more opportunities to cultivate their ability, especially leadership.Therefore, after mastering their professional knowledge, students are advisable to take part in a sensible way.新东方：2011年12月英语四级作文预测4篇(4)

四、My Opinion on Campus Lectures

1.大学校园里的讲座丰富多彩

2.听讲座的益处

3.你对在大学校园里听讲座的评论

首段现象描述：

On many campuses, it has become a prevalent phenomenon for college to hold various lectures.Meanwhile, a host of parents or teachers encourage and advocate college students to attend these lectures to gain a favorable position in academic learning.Taking a look around, we can find a great many lectures like this: lectures about job-hunting, cet-46 and so on.利分析(支持方观点)

A number of individuals prefer or favor these lectures.In their eyes, these wide opportunities will enhance students’ over-all development and competitiveness, because lectures by famous professors will enrich their knowledge and broaden their horizons.Then, holding lectures calls for less time, energy, and money;however, the result of learning is always as satisfactory.Then, what excites many teachers is that students’ academic learning may be affected positively by much extra-curriculum information.我的看法(或建议)