英文论文中使用的时态

一般过去时也有以下几种方式在 Method 的部分中常用：
英文论文写作各部分应用时态解析（图 5） Results
在描述实验结果时，通常用一般过去时。 e.g.Analysis of the identified gene set revealed the induction of a broad-spectrum antipathogen response. 如果是提及图片、表格及图像时，则需要使用一般现在时。 e.g.Table 1 presents the structural units.
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1）Abstract 摘要主要以一般现在时为主，比如研究背景介绍和现状下图中的叙述背景细节都建议采用一般现在时。 e.g.This paper analyses the impact of high temperatures on certain species.
如果涉及到所做的工作下图中的调查过程，也可以使用现在完成时或者是一般过去时。e.g.There has been a large body of research regarding the effect of carbon emissions on climate change.
英文论文写作各部分应用时态解析（图 6）
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Discussion 实验结果出来后，我们需要对它进行讨论（discussion）中间要掺杂自己的思考，以及依据为何，这里
也是比较考验逻辑的一个部分。 在用实验结果引申结论时，建议使用一般现在时。 e.g.Our data suggest this pathway may be responsible for… 如果是概括性的得出结论，则需要用一般过去时。 e.g.We discovered a new therapeutic target for… 假如有说明后续研究的需要，用一般将来时最佳。 e.g.In future studies，we will examine the effects of…

如何撰写英文科技论文时态与语态部分（一）TENSE（时态）撰写英文论文会涉及时态。

通常科技论文采用的时态为一般过去时，但在列表、进行统计分析或描述不争事实时应该采用一般现在时。

例如："Table 4 shows that..."（列表）；"These values are significantly greater than those of the females of the same age ，indicating that the males grew more rapidly” (统计分析)；“Water was added and the towers became damp ,which proves again that water is wet(不争事实)。

但根据Day(1989)的建议,论文中凡涉及研究领域内已存在的理论和知识(包括他人在此之前发表过的论文)时均应采用一般现在时来表示对理论贡献者们的尊重。

以此推理,Introduction 和Discussion的绝大部分内容(即涉及研究领域内已有的理论和知识的部分)应采用一般现在时。

按照Day的建议,摘要通常应该采用一般过去时,因为作者在这里主要是介绍自己的工作。

（二）VOICE (语态)除了时态,语态也是撰写英文论文应该注意的方面。

读者可能会发现大量英文科技论文都采用被动语态,这虽然是事实,但并不是规则。

其实,使用被动态语态往往违背科技论文"精确”、"简洁”的要求。

譬如"It was found that” 就远没有"I found ”来的清晰明了。

我的一位同事在博士论文中通篇采用被动语态，结果答辩时考官不明白他到底是在引用别人的工作还是自己的工作。

科技论文中主动语态和被动语态可以并用，具体使用哪种语态首先取决于句子所要强调的重点，同时应该考虑表达的简练和精确。

英文论文数据结果表示方式据学术堂了解，英文表达有16种时态,论文中要用到的时态主要有一般现在时、一般过去时和现在完成时.一般现在时：主要用于不受时间限制的客观存在事实的描述,或发生或存在于写论文之时的感觉、状态、关系等的描述或致谢的表述等.值得注意的是,出于尊重,凡是他人已经发表的研究成果作为previously established knowledge,在引述时普遍都用一般现在时.一般过去时：用于写论文中作者自己所做工作的描述.例如描述自己的材料、方法和结果.现在完成时：完成时少用.现在完成时把过去发生的或过去已完成的事情与现在联系起来.比如在介绍研究方法、分析某个问题或提出某个论证时,使用一般现在时.在叙述对本人或他人近期的工作或认识时,采用一般过去时或过去完成时.叙述结论或提出建议时,可使用一般现在时以及使用may,should,could等助动词.例如,当提到本文、此图、此表等说明了、表达了什么时要用一般现在时,而不用一般过去时.This paper describes The focus of this paper is Figure 1 shows Most of the mon condensation polymers are listed in Table 1-1.结论部分可以使用过去时强调过去的研究成果,采用现在时或将来时表达未来的研究方向或研究前景.Although the study found evidence of tillage and irrigation within the study area,from the data collected it was not possible to determine if the effects of agriculture upstream cause (or caused) higher levels of total nitrogen downstream. Further studies are therefore necessary to determine the effects of agriculture on the health of Stringybark Creek.。

英语作文中的时态是什么What is the tense used in English composition?When writing an English composition, the tense used is an important aspect to consider. The tense used in a composition can affect the clarity and coherence of the writing, and can also convey different meanings and implications.The most commonly used tenses in English compositionare the present tense, past tense, and future tense. Eachof these tenses has its own unique characteristics and uses, and can be used to convey different ideas and perspectives.The present tense is used to describe actions that are happening right now, or are ongoing. For example, "I am writing this composition." The present tense can also be used to describe general truths or habits, such as "Water boils at 100 degrees Celsius."The past tense is used to describe actions or events that have already happened. For example, "I wrote a composition yesterday." The past tense can also be used to describe hypothetical situations or actions that did not happen, such as "If I had studied harder, I would have passed the exam."The future tense is used to describe actions or events that will happen in the future. For example, "I will write a composition tomorrow." The future tense can also be used to express predictions or expectations, such as "It will rain tomorrow."In addition to these basic tenses, there are also more complex tenses such as the present perfect, past perfect, and future perfect. These tenses are used to describe actions that have been completed or will be completed at a specific point in time, or to express a sense of continuity or duration.Overall, the tense used in an English composition should be chosen carefully to ensure that the writing isclear, coherent, and effective in conveying the intended meaning and message. By understanding the different tenses and their uses, writers can create compositions that are engaging, informative, and well-written.。

如何在科技论文中使用时态英语谓语动词时态共有16种，在英文科技论文中用得较为频繁的主要有三种：即一般现在时、一般过去时和将来时。

正确地使用动词时态是科研写作的基本功，我们在撰写英文论文时，如不能正确选用时态，常常会改变文章所要表达的意思，从而影响评审专家与读者的理解。

一篇典型的科技论文有一个基本的框架结构：Abstract (综述科研背景，提出研究的问题和假设(hypothesis))，Materials and Methods (描述自己的研究方法)，Results (分析所得的研究结果)，Discussion (深入讨论研究结果的意义并简要指出将来的研究方向)。

我们现根据这个论文框架，就一些规律性问题做些探讨，希望对大家有所帮助。

首先应该把握以下三个基本要点：1、一般现在时：主要用于不受时间限制的客观存在事实的描述，或发生或存在于写论文之时的感觉、状态、关系等的描述或致谢的表述等。

值得注意的是，出于尊重，凡是他人已经发表的研究成果作为"previously established knowledge"，在引述时普遍都用一般现在时。

2、一般过去时：用于写论文中作者自己所做工作的描述。

例如描述自己的材料、方法和结果。

3、一般将来时：用于撰写论文之后发生的动作或存在的状态。

例如提出下一步的研究方向。

摘要（Abstract）：摘要反映我们自己的研究结果，一般采用过去时。

概述（Introduction）：（1）概述中的研究背景通常会引用相关学科中广为接受的原理或事实，以及你所做研究的重要性，这些通常采用现在时。

例如：Genomics provides crucial information for rational drug design.（2）在概述中也可能引用与你从事项目相关的一些研究结果，为表达你对该研究结果仍坚信其正确性及相关性，即使已经是很久以前的研究结果，可使用现在时。

英文科技论文写作技巧与时态表达总结英语谓语动词时态共有16种，在英文科技论文中用得较为频繁的主要有三种：即一般现在时、一般过去时和将来时。

正确地使用动词时态是科研写作的基本功。

此次分享的是英文科技论文写作技巧与时态表达总结。

首先应该把握以下三个基本要点：1、一般现在时：主要用于不受时间限制的客观存在事实的描述，或发生或存在于写论文之时的感觉、状态、关系等的描述或致谢的表述等。

值得注意的是，出于尊重，凡是他人已经发表的研究成果作为"previously established knowledge"，在引述时普遍都用一般现在时。

2、一般过去时：用于写论文中作者自己所做工作的描述。

例如描述自己的材料、方法和结果。

3、一般将来时：用于撰写论文之后发生的动作或存在的状态。

例如提出下一步的研究方向。

摘要(Abstract)：摘要反映我们自己的研究结果，一般采用过去时。

概述(Introduction)：(1)概述中的研究背景通常会引用相关学科中广为接受的原理或事实，以及你所做研究的重要性，这些通常采用现在时。

例如：Genomics provides crucial information for rational drug design.(2)在概述中也可能引用与你从事项目相关的一些研究结果，为表达你对该研究结果仍坚信其正确性及相关性，即使已经是很久以前的研究结果，可使用现在时。

例如：Many of the lakes and wetlands in the region are located in craters or valleys blocked by early Pliocene lava flows (Ollier & Joyce, 1964).Garcia (1993) suggested that under certain conditions, an individual’s deposit income is the same as the income from purchased national debt, thus changes in the amount of bank loans and deposits caused by changes in the amount of reserves will eventually affect the bond price.需要注意的是如果引用的是一些已经过时或失效的科研结果，动词要使用过去时。

英文科技论文不同部分的常见时态一篇英文科技论文通常由题目、摘要、关键词、引言、方法、讨论、结论、参考文献等部分构成。

为了进一步加深理解和灵活把握英文科技论文写作中的动词时态，医刊汇编译现就分别对英文科技论文中不同部分常见的动词时态进行介绍，并引用国际顶级期刊中的例子加以说明。

需要注意的是，英文科技论文中每一部分动词的时态都不是一定的，具体还需要根据叙述内容和上下文语境确定。

一、题目(title)。

题目通常为一个不完整的句子或短语，一般不涉及动词的时态。

如果使用一个简单句作为题目，通常使用一般现在时，例如：Data management：India needs agency for energy data.二、摘要(abstract)。

摘要中最常见的时态是现在完成时和一般现在时。

现在完成时通常用于表达过去研究中已有的方法和发现，一般现在时用于表达现阶段在某个研究方面的不足或空白。

例如：Attacks on health care have sparked a large-scale exodus of experienced health workers.三、引言(introduction)。

英文科技论文的引言通常先介绍研究的背景，之后逐步缩小，最后引出论文所涉及的具体问题。

在写作过程中，在讨论他人之前的研究时，通常使用一般过去时，例如：They specifically focused on men with congestive heart failure，diabetes，and chronic airways disease.一般情况下，也可以使用现在完成时描述他人已经完成的研究或工作。

例如：Thus，improvement of population health and health equityneeds intersectoral action and social participation，which have been introduced by many Latin American countries.在引言中，涉及一般事实或真理以及表达作者的写作目的时，通常使用一般现在时，例如：Underground injection is probably the easiest route to sequestration.四、方法(method)。

硕士论文英文摘要时态硕士论文英文摘要时态原则上讲，以上中文摘要编写的注意事项都适用于英文摘要，但英语有其自己的表达方式、语言习惯，在撰写英文摘要时应特别注意。

1) 英文摘要的时态。

英文摘要时态的运用也以简练为佳，常用一般现在时、一般过去时，少用现在完成时、过去完成时，进行时态和其他复合时态基本不用。

一般现在时。

用于说明研究目的、叙述研究内容、描述结果、得出结论、提出建议或讨论等。

分别举例如下：This study(investigation) is (conducted, undertaken) to…The anatomy of secondary xylem(次生木质部) in stem of Davidia involucrata (珙桐) and Camptotheca acuminata (喜树) is compared.The result shows(reveals)…，It is found that…The conclusions are…The author suggests….涉及到公认事实、自然规律、永恒真理等，当然也要用一般现在时。

一般过去时。

用于叙述过去某一时刻(时段)的发现、某一研究过程(实验、观察、调查、医疗等过程)。

例如：The heat pulse technique was applied to study the stemstaflow (树干液流) of two main deciduous broadleaved tree species in July and August,1996.需要指出的是，用一般过去时描述的发现、现象，往往是尚不能确认为自然规律、永恒真理的，而只是当时如何如何;所描述的研究过程也明显带有过去时间的痕迹。

现在完成时和过去完成时。

完成时少用，但不是不用而过去完成时可用来表示过去某一时间以前已经完成的事情，或在一个过去事情完成之前就已完成的另一过去行为。

英语科技论⽂表述中常⽤的时态英语句⼦中作谓语的动词发⽣的时间和存在状态不同，其表达形式亦不同，谓语动词的这种不同的形式称作时态。

在写句⼦的时候，准确地把握句⼦的时态是科技论⽂写作中的关键之⼀。

英语句⼦中的谓语动词虽然有16个时态，但在科技论⽂中常⽤的只有5种，即⼀般现在时，⼀般过去时，⼀般将来时、过去完成时和现在完成时。

⽽⽤得最为频繁的只有⼀般过去时和⼀般现在时。

(1)⼀般现在时态⽤于正式发表的内容。

Optically active amines bearing the stereogenic center as the position areimportant compounds because of their broad range of applications and theirpharmacological properties.⽤于前⾔中的⼀般性背景叙述。

In most cases, the pharmacological activities of these amines are relatedto the configuration of the stereogenic center.⽤于图或表的引出。

Fig.2 representsthe binding mode of the substituents of R-amines 1~6.The results are collected in Table 1.⽤于对实验结果的讨论。

Amphetamine shows a lower E value than those of its methoxy analogous,which is due to the fact that (R)-methoxyamphetamines react faster than(R)-amphetamine and that (S)-amphetamine is transformed more quickly than(S)-methoxyamphetamines. In the same way, the higher E value for mexile- tineis mainly a consequence of the slower reactivity of its (S)-enantiomer. Theseresults can be explained to a large extent on the basis of the size of thesubstituents attached to the stereocenter and size of the small pocket.⽤于⼀般性真理的描述。

英语作文的时态确定（中英文实用版）Determining the Tense in English Essay Writing在英语作文写作中，时态的确定至关重要。

It is essential to decide on the appropriate tense when writing an English essay.This choice can significantly impact the clarity and coherence of your composition.选择合适的时态可以增强文章的清晰度和连贯性。

Past tense is commonly used when describing events that have already occurred, such as in narrative essays or when discussing literature.在叙述已经发生的事件或讨论文学作品时，通常会使用过去时。

However, present tense is favored for providing general statements or introducing the subject matter at hand.然而，对于提出一般性陈述或引入手头上的主题，一般会使用现在时。

Future tense comes into play when discussing predictions, intentions, or hypothetical scenarios.在讨论预测、意图或假设情景时，将来时就会派上用场。

It"s important to maintain consistency within each paragraph and throughout the entire essay to avoid confusion.在每个段落以及整篇文章中保持时态的一致性至关重要，以免造成混淆。

英语摘要中时态和语态的运用在英语摘要中，时态的使用主要有以下几点：1. 一般现在时：用来描述事实、经验或者常规动作。

例如，“The study shows that smoking causes cancer.”（这项研究表明吸烟会导致癌症。

）2. 现在进行时：用来描述正在进行的动作。

例如，“The researchers are currently studying the effects of climate change on biodiversity.”（研究人员目前正在研究气候变化对生物多样性的影响。

）4. 过去进行时：用来描述过去一些具体时间点正在进行的动作。

例如，“At 5 p.m. yesterday, I was watching a movie.”（昨天下午5点，我正在看电影。

）5. 完成时态：用来描述已经完成的动作或者一些时间点之前已经发生的动作。

例如，“The researchers have published several papers on this topic.”（研究人员已经在这个课题上发表了几篇论文。

）1. 主动语态：主语执行动作。

例如，“The government implemented a new policy to reduce pollution.”（政府实施了一项新政策来减少污染。

）2. 被动语态：主语接受动作。

被动语态常用于强调行为的对象而不是执行者。

例如，“The new policy was implemented by the government to reduce pollution.”（新政策是政府实施的，旨在减少污染。

）。

科学论文中使用的时态一般分为现在时和过去时。

在描述理论、事实、公认真理、现象或近期发现时，使用现在时; 在描述先前的研究、数据收集、分析、结论和讨论时，使用过去时。

1. sci现在时的英文表达在科学论文中，现在时通常用于以下情况：- 描述普遍真理或自然定律：The law of conservation of energy states that energy cannot be created or destroyed.- 强调当前的常规做法或观点：Current research shows that the Earth's climate is warming at an unprecedented rate.- 表达已经发表的结果：Smith et al. (2020) demonstrate that the new drug has a significant impact on cancer cells.2. sci过去时的英文表达在科学论文中，过去时通常用于以下情况：- 描述先前的研究或实验：Previous studies have shown that the enzyme has catalytic activity.- 描述数据收集、分析和发现：The results of the experiment indicated that there was a strong correlation between the variables.- 总结先前的研究成果：Smith and colleagues (2010) reportedthat the protein expression levels were significantly altered inthe diseased cells.3. sci现在时和过去时的转换在科学论文中，科学家经常需要在描述自己的研究成果时使用现在时，而在回顾和总结自己的研究时使用过去时。

英语作文的时态有几种形式There are several forms of tenses in English writing, including present, past, future, present perfect, past perfect, future perfect, present continuous, past continuous, future continuous, present perfect continuous, past perfect continuous, and future perfect continuous.Present tense is used to describe actions that are happening currently or regularly. For example, "I am studying English every day."Past tense is used to describe actions that have already happened. For example, "I studied English yesterday."Future tense is used to describe actions that will happen in the future. For example, "I will study English tomorrow."Present perfect tense is used to describe actions thathave happened in the past and continue to have an effect in the present. For example, "I have studied English for three years."Past perfect tense is used to describe actions that happened before another action in the past. For example, "I had studied English before I moved to the United States."Future perfect tense is used to describe actions that will be completed before another action in the future. For example, "I will have studied English for five years by the time I graduate."Present continuous tense is used to describe actions that are happening currently and will continue in the future. For example, "I am studying English this semester."Past continuous tense is used to describe actions that were happening in the past at a specific time. For example, "I was studying English at 9 o'clock last night."Future continuous tense is used to describe actionsthat will be happening in the future at a specific time. For example, "I will be studying English at 10 o'clock tomorrow morning."Present perfect continuous tense is used to describe actions that started in the past and continue up to the present. For example, "I have been studying English for three hours."Past perfect continuous tense is used to describe actions that were happening continuously before another action in the past. For example, "I had been studying English for three hours before I took a break."Future perfect continuous tense is used to describe actions that will have been happening continuously before another action in the future. For example, "I will have been studying English for five hours by the time my class ends."In conclusion, there are many forms of tenses inEnglish writing, and it is important to use them correctly to convey the intended meaning.。

学术论文常用词汇学术论文的语言表达一、时态时态是个比较复杂的问题虽然有一般的规则但往往在实际文章中很难把握总体的规则已在前边讲过需要重申的是在同一段落中要避免时态跳跃详见学术论文的写作最常见的描述一般现象的时态是一般现在时有时也用一般过去时或一般将来时需要注意的语法In recent years 作时间状语时通常要用完成时In recent years, Plesch and coworkers have concluded that many so-called cationic polymerizations do not proceed through intermediates of an ionic nature.二、数词数也有其复杂化特别是在学术论文里有是很难顾及数上的逻辑但一般不将逻辑上的问题视为语法错误只须注意在一个句子中的数和谓语动词的统一即可以下是需要注意的语法不规则变化的单复数单数复数criterion criteria 依据phenomenon phenomena 现象medium media 介质radius radii 半径index indices 指数appendix appendices 附录stimulus stimuli 刺激basis bases 基础2synthesis syntheses 合成matrix matrices 基体Novel biomaterials with improved, specific biological action are being developed using polymers that are responsive to environmental stimuli.一些数有特殊性的名词data, kinetics 通常作复数名词research, work: 不可数名词The data in Table 1 are obtained from the reactions at different temperatures.The kinetics of polymerization within each droplet are the same as those for the corresponding bulk polymerization.Much research has been done to redirect the tropism of retroviruses by engineering the envelope glycoprotein.Most research on poly(ortho esters) has focused on the synthesis of polymers.一些结构的数<主谓的统一>one of 复数名词单数none of 复数名词复数none of 单数名词/不可数名词单数no 复数名词复数no 单数名词/不可数名词单数a kind of 单数名词单数this/that kind of 单数名词单数these kinds of 复数名词复数复数名词of this/that kind 复数sort 与kind 类似a type of 单数名词单数a series of 复数名词复数a class of 复数名词复数the number of 复数名词单数a number of 复数名词复数Ara-C is one of most important antitumor agents, especially used in the treatment of various leukaemias.One of possibilities for enhancing the pharmacological properties is to link it to a carrier. Biocompatibility is one of the main criteria for the selection of a particular biomaterial. 3 Controlled drug delivery technology represents one of most rapid advancing areas of science in which chemists are contributing to human health care.Several models have been proposed but none appear to be generally applicable.None of the presently used ones are applied rigorously.Thus far no studies have conclusively demonstrated long-term value of any of the cardiac gene therap approaches.This type of termination is often referred to as spontaneous termination.A number of polymer backbones that are potentially degradable are detailed in the text. The number of mechanisms which have been proposed to explain the stereopecificity of Ziegler-Natta catalysts.* The number of 复数名词: 整个做主语时谓语应为单数; 但此句的动词have 是从句的谓语而从句是形容mechanisms.在其它的从句谓语中也是同样如: One of the mechanisms which have been……A series of telomers reported in table 1 were then synthesized.A diverse range of mechanisms have been developed.Polymers are a promising class of biomaterials that can be engineered to meet specific end-use requirements.The most important class of poly(amides) for controlled release are the poly(amino acids). The majority of poly(anhydrides) are prepared by melt-condensation polymerization.A wide variety of natural and synthetic polymers have been used to fabricate tissue-engineering matrices.后面通常要用复数名词对可数名词而言various differentmost all many severalone of many ofkinds ofa number of the number ofa (wide) variety of a class ofa series of a wide range ofDozens of different types of receptors are present on the average mammalian cell.4In a number of special applications (e.g. contact lenses and skin-grafting materials), additional requirements such as transparency should be considered when selecting a polymer.Many of these transmembrane proteins are receptors.Some polymers are highly crystalline primarily because their structure is conductive to packing, while others are crystalline primarily because of the secondary forces. For still other polymers, both factors may be favorable for crystallization.形容可数名词的量词a few many a number of形容不可数名词的量词a great/small/certain amount of a great/good deal of形容可数和不可数名词均可的量词a lot of lots ofAlthough a few polymers may be completely amorphous and a few completely crystalline, most polymers are partially or semi-crystalline in character.The use of IPNs has received a great deal of attention in recent years and different kinds of IPN have been synthesized with different compositions.The major amount of work on size distributions has been on polyesters and polyimides.A sizeable amount work has been published on the copolymerizations of various cyclic monomers. 以下结构的谓语的数由前一个决定, as well as……由较靠近谓语动词的决定not only……but also……either……or……neither……nor……三、冠词冠词是最易犯错误的地方一定要注意否则编辑的负担极重因为每句话都会用到冠词最普通的规则如下单数名词前一般要加冠您身边的论文好秘书：您的原始资料与构思,我按您的意思整理成优秀论文论著,并安排出版发表，企鹅1550116010 、766085044自信我会是您人生路上不可或缺的论文好秘书词 a , the 等但有些情况可不加复数名词前一般可不加冠词也可加the, these, those.5The molecular weight of a polymer is of prime importance in its synthesis and application.The rate constant can be expressed by an Arrhenius type relationshipK = A e -E/RTWhere A is the collision frequency factor, E the Arrhenius activation energy, and T the Kelvin temperature. A plot of lnK versus 1/T allows the determination of both E and A from the slopeand intercept, respectively.When a water-insoluble or only slightly water-soluble monomer is added, a very small fraction dissolves and goes into solution. A large but still small portion of the monomer enters the interior hydrocarbon part of the micelles. The largest portion of the monomer is dispersed as monomer droplets.被修饰的名词前要加the:There has been a rapidly increasing effort in the last ten to fifteen years toward the synthesis of new polymers with markedly higher temperature resistance than those previously available.The catalysts usually must be prepared at the low temperatures since most of them become heterogeneous when prepared at or warmed up to the temperatures above about -40 . 四从句分词不定式这些是写作时常用且必须用到的结构一定要掌握在学术论文中从句分词不定式通常用来作修饰Applications in the relatively new field of tissue engineering, where polymers are used to assist regeneration of three-dimensional tissue structures, are more and more integrated with biological demands.There are three general synthetic approaches that have been used to produce polymers with increased thermal stability.If certain symmetry requirements are met, the molecules are able to pack into an ordered, lattice arrangement and crystallization occurs. The temperature at which this occurs is Tm. There are at least two mechanisms through which the infectivity of a vector can be blocked.Biodegradable polymers containing ˋhydrolysable ˊgroups in their chains, which are susceptible to biodegradation to low molecular weight, nontoxic products, have also been considered for controlled drug delivery systems.Polymers possessing high strength, solvent and chemical resistance, and serviceability at high temperatures would find a variety of uses.6The challenge facing cell and molecular biologists is to decipher how cellular events occur.A general problem encountered in many of the polymerization systems has been a difficulty in obtaining polymers of sufficiently high enough molecular weight to have reasonable strength properties.Another approach to obtain rigid polymer chains is by the synthesis of spiro polymers. 五标点英文中一句话结束要用句号注意避免过长的句子这点与汉语中常用逗号的习惯不同请注意以下结构的标点…… such as A and B ………… such as A, B and C ………… , such as A, ………… , for example, ………… , for example ………… ,e.g., ………… ,i.e., …………, respectively.四、掌握一些学术论文常用的短语结构可大大降低写作的难度In order to meet all of these criteria, the vector must deliver the gene accurately. To overcome this problem, it would be advantageous to pseudotype lentiviral vectors withtargeted MLV envelopes.Besides identifying suitable proteases for targeting, the success of thisprotease-targetingstrategy relies on the accessibility of the linker to protease cleavage.We have focused our investigations on the in vitro and in vivo biological response of a mousecell line.On the contrary, the homotelomer derivative 11 exhibits no substantial loss of cytotoxicity compared to free Ara-C.After more than three decades of development, in which numerous polymers have been used to replace body parts, clinical success is still relatively rare.7In some cases, polymeric materials for drug delivery must satisfy additional requirements, such as environmental responsiveness (e.g. pH- or temperature dependent phase or volume transformations.)Owing to the nature of these interactions, surface modification strategies have been used to。

英文摘要中语态和时态的用法In academic writing, it is important to correctly use tenses and voices to accurately convey information and maintain coherence. This paper aims to explore the usage of tenses and voices in English abstracts.Tense usage in abstracts plays a vital role in describing research findings and outcomes. The present tense is typically used to introduce the topic and provide a general overview of the study. For example, "This paper investigates the impact of climate change on biodiversity in tropical rainforests." The present tense is also used when discussing commonly accepted facts, such as "Previous studies show that deforestation leads to a loss of habitat."However, the past tense is utilized when discussing the methods and results of a research study. For instance, "Data was collected from various rainforest sites using transect sampling." It is crucial to remember that the past tense should be used consistently throughout the abstract when discussing the study's specific details and findings. This creates a clear and coherent narrative for the reader.On the other hand, the future tense is rarely used in abstracts, as they focus on providing a summary of completed research. Nevertheless, there might be exceptions where researchers may briefly mention their plans or predictions for future research. For instance, "Further investigation is needed to determine the long-term effects of climate change on specific rainforest species." Voice is another important aspect of abstract writing, as it affectsthe tone and clarity of the text. Both active and passive voices have their own uses and are employed depending on the emphasis and subject of the sentence.The active voice is commonly preferred in abstracts as it provides clarity and conciseness. It allows the reader to easily identify the subject of the sentence and understand the study's main focus. For example, "The researchers conducted a survey to assess the impact of pollution on marine life." In this sentence, the subject "researchers" is clearly performing the action "conducted." This voice is especially useful when discussing methods, results, and conclusions.In contrast, the passive voice is less commonly used in abstracts but can be effective in certain situations. It is used when the focus is on the object of the action rather than the subject. For instance, "The impact of pollution on marine life was assessed through a survey." This sentence highlights the impact of pollution, rather than the researchers themselves. However, it is important to ensure that the use of passive voice does not lead to ambiguity or confusion, and that the sentence remains concise and clear.To sum up, the correct usage of tenses and voices in abstracts is crucial for accurately conveying information and maintaining coherence. The present tense is typically used for general statements and background information, while the past tense is used for specific methods and results. The future tense is rarely used, but might be employed briefly for future research plans. The active voice is preferred for clarity and conciseness, while the passive voice may be used for emphasizing the object of the action.By understanding and appropriately incorporating these aspects, writers can effectively communicate their research findings in their abstracts.在学术写作中，正确使用时态和语态对于准确传达信息并保持连贯性非常重要。

论文摘要的时态基本上有两种 : 一般现在时、一般过去时。

由于学术论文写作通常采用一般现在时, 摘要也多用一般现在时。

目的、方法、结果及结论部分多用一般现在时 , 背景介绍常采用一般过去时。

一般现在时用于描述研究目的和范围、研究内容、结果和结论 ;一般过去时用于描述论文撰写前作者已做的工作, 也可用于表示转述已发表文献的报导、讨论和研究内容。

语态与人称主张多采用被动语态。

因为使用被动语态不仅可以省略施动者, 避免出现“WE”表示方式, 而且还可以使需强调的事物做主语而突出了它们的地位,有利于说明事实。

英文摘要往往采用第三人称的被动语态, 可以避免提及有关执行者, 使行文显得客观。

同时, 被动语态句子在结构上有较大的调节余地, 有利于使用恰当的修辞手段, 扩展名词短语, 扩大句子信息量。

但有时采用主动语态比用被动语态在结构上更简练。

英文摘要根据《ＥＩ》的要求, 一篇较好的英文摘要应较好地回答以下4 个方面的问题:1)what you want to do(目的)，2）How you did it (方法) ，3) What result didi you getand what conclusions can you draw ( 结果和结论); 4) What is original in yourpaper ( 创新独到之处) 。

英文摘要正文的写作模式英文摘要语篇结构固定, 内容完整。

英文摘要的篇章结构通常涉及主题句、拓展句和结论句三部分, 涵盖了研究的背景、目的和范围, 研究的方法、手段或步骤, 研究的结果, 研究得出的主要结论或建议四个方面。

由于摘要字数有限，所以研究的背景、目的和范围可省略, 写作的重点放在后三个方面。

英语作文什么时态In English writing, the choice of tense depends on the context and the narrative you wish to convey. Here are some common tenses used in English essays:1. Present Simple: 。

Used for general truths, habits, and routines.Example: "The sun rises in the east."2. Present Continuous:Used for actions happening at the moment of speaking or ongoing actions.Example: "She is writing an essay on English tenses."3. Present Perfect:Used for actions that happened at an unspecified time before now or for actions that have relevance to the present moment.Example: "I have finished my homework."4. Past Simple:Used for actions that occurred and ended at a specific time in the past.Example: "He studied English literature in college."5. Past Continuous:Used for actions that were ongoing at a specific time in the past.Example: "They were playing football when it started raining."Used for actions completed before another action in the past.Example: "She had already eaten dinner when I arrived."7. Future Simple:Used for actions that will happen in the future.Example: "We will visit London next summer."8. Future Continuous:Used for actions that will be ongoing at a specific time in the future.Example: "This time next week, I will be attending a conference."Used for actions that will be completed before a specific time in the future.Example: "By the end of the year, he will have graduated from university."When writing an essay, it's essential to maintain consistency in the chosen tense throughout unless there's a clear reason for shifting tenses to indicate a change in time or perspective. Additionally, consider the narrative tone and purpose of your essay when selecting the appropriate tense to effectively convey your message to the reader.。