论文写作中常出现的语法问题
有的语法对科技论文写作可能关系不大，如将来式的用法，但同样一些语法对科技论文写作特别重要，清晰的实验描述和准确的思想表达对科技写作尤其重要，宁愿多写一些句子，也要把事情表达清楚，也就是不能为达到简洁而牺牲清晰。句子可以写得简单，用词可以有些单调，但语句的意思一定要清楚。科技写作的语法特点就是为了保证语句的清晰，不同的人对英语语法的掌握程度不同，下面介绍一些科技写作中经常遇到的语法问题。
1. 主语和谓语的单数和复数要一致
英语中名词有它的单数和复数形式，动词也有它的单数和复数形式，二者要一致。单数主语 (subject) 名词要用动词 (verb) 的单数 (singular) 形式，复数主语名词要用动词的复数 (plural) 形式。我们写中文的不太习惯英语的这种写法，很难做到不假思索地配对，需要特别留心才能不出错误，特别是当主语名词和动词被分开时。试看下面的例句。
A high percentage of peptides that are made of amino acids are present in the sample.
A high percentage 才是真正的主语，而不是邻近的 amino acids，所以应该用单数形式。
宜改为: A high percentage of peptides that are made of amino acids is present in the sample.
让事情更复杂的是英语名词被分为不同的种类，其中的一类叫集合名词。它既可以当单数用词也可以当复数用。集合名词当整体来讲时是单数，每个成员作为个体时用复数。
The number of mice in the experiment was increased.
A number of mice have died.
All of the samples were analyzed.
All of the safety procedures was strictly followed.
代词 none 既可以是单数也可以是复数。当 none 后面的词是单数时，用单数动词；当 none 后面的词是复数时，用复数动词 .
None of the information was useful.
None of the animals were starved. 描写数量、重量、体积、时间等的词用单数，但如果是分次添加或减少时用复数。在这个意义上同集合名词类似。
1.5 ml was added.
10 g was added .
6 hours was the required incubation time.
简写的数量单位， 如 mg, ml, s 等，单数和复数的写法是一样的，如 1mg, 5 mg.
一些词如 series, type, portion, class, 要用单数形式。
A series of derivatives of penicillin was prepared.
A large portion of the reports is focused on how to deal with the increased cost. 2. 修饰语同主语名词关系上要一致
当用 1) 动名词 (gerund)，2) 分词短句 (participle)，3) 不定式短句 (infinitive) 作修饰语时，修饰语中的动词要同主句中的主语名词关系上要一致。科技杂志论文中有这种语法错误的情况较多。严格来讲这只是种语法错误，一般不影响对句子的内容的理解，所以很多作者不太注意。编辑和阅稿人有时也没有严格要求改正。比如下面就是Nature杂志20xx年第439卷中的一个例子。
Using the enhancer GAL4/UAS expression system, short-term memory traces of aversive and appetitive olfactory conditioning have been assigned to output synapses of subsets of intrinsic neurons of the mushroom bodies.
1) 动名词
After finishing the purification, the activity of the isolated compound was then
studied.
We or I 是动名词 finishing 形式上的主语，同主句的主语activity不一致。 宜改为: After purification was finished, the activity of the isolated compound was then studied.
或: After finishing the purification, we studied the activity of the isolated compound.
Treated with the new drug, the blood cholesterol levels of participants were lowered by an average of 30%.
宜改为: Treated with the new drug, participants showed an average of 30% decrease in their blood cholesterol levels.
2) 分词短句
The iron concentration was determined using the Fenton reaction method. The iron concentration 同 using the Fenton reaction method 关系上不一致。 宜改为 : The iron concentration was determined by the Fenton reaction method. 或 : We determined the iron concentration using the Fenton reaction method. When measuring the atmospheric level of carbon dioxide, air samples from a remote place, such as an island, is preferred.
宜改为: When the atmospheric level of carbon dioxide is measured, air samples from a remote place, such as an island, is preferred.
3) 不定式短句
To further investigate the potential role of biking in causing infertility, an expanded population of biking athletes was surveyed.
不定式短语的形式主语是 we or I，同主句主语 population 不一致。
宜改为: To further investigate the potential role of biking in causing infertility, we surveyed an expanded population of biking athletes.
To confirm the diagnosis, blood test was ordered.
宜改为 : To confirm the diagnosis, the doctor ordered blood test.
3. 主语和主语的行动 (谓语) 在逻辑上要一致
由于一些中文和英文的表达方式不同，把中文直接翻译成相应的英文会讲不通。一个经常被引用的语句是 “price is cheap”。中文可以说价格便宜，但英文只能说价格高或低。物品可以说 cheap or expensive。用中文的表达方式来写英文，会出现主语和主语的行动在逻辑上不一致。在写一个句子时要注意行动的真正主语名词是什么。下面是一些例子。
The highest antibiotic
不是 production 而是 production yield.
宜改为: The highest antibiotic production yield was obtained at 48 h.
The scavenging activity for hydroxyl radicals was based on Fenton reaction. 不是 activity 而是 assay of activity
宜改为: The assay of scavenging activity for hydroxyl radicals was based on Fenton reaction.
The pharmacological compounds of ginseng were identified.
药物活性化合物应该是 pharmacologically active compounds.
宜改为: The pharmacologically active compounds of ginseng were identified.
4. 代名词和其代理的先行词要一致
代名词和其代理的先行词要在人称、单数或复数、和性别上一致。一些常见的代词是: he, his ( 阳性单数 ); she, her ( 阴性单数 ); it, its ( 单数 ); they, their, these, those ( 复数 ); that, this ( 单数 ). 比如下面的例句中, compounds 和 their 一致, protein 和 it 一致。
Many related compounds were synthesized and their antivirus activities were studied.
Growth hormone is a protein. It promotes human body growth.
下面的例句中, the 应该用 their 取代。
The potential antioxidant capacity of compound A and compound B could be deduced from the protective effects against oxidative stresses.
宜改为 : The potential antioxidant capacity of compound A and compound B could be deduced from their protective effects against oxidative stresses.
用代名词时除了要保持一致外，还要避免代理不清的情况出现，以免不清楚它们到底指什么而引起误解。
The crude sample was dissolved in water and extracted with organic solvent. It was then evaporated to yield the product.
It 指 organic layer 还是指 water layer? 不明确，最好不用it.
宜改为：The crude sample was dissolved in water and extracted with organic solvent. The organic layer was then evaporated to yield the product.
During meal hormones are released after which blood flow increases in the stomach.
Which 既可以代表 meal 也可以代表 hormones, 容易产生误解 .
宜改为： During meal hormones are released. After their release stomach blood flow increases.
5. 位置的强调作用
在英语写作中，若要强调某件事情，就把它放在句子的前面。中文写作中, 有关句子的条件, 时间等的修饰句都是放在前面，而主句总是放在后面。而英文中即可以把条件或修饰句放在前面，也可以放在后面。放在前面就表示你要强调修饰句的条件。比如:
Before the hurricane arrived, most of the people have moved out.
Most of the people have moved out before the hurricane arrived.
在英语中两种位置关系都可以。前者强调在 hurricane 来之前，后者强调 moved out . 而在中文中，只有一种说法，反过来说“大多数人都离开了在hurricane 来之前” 就不对了。按中文的位置关系直译成英文，往往会不确切。同样按英文的位置关系直译成中文也是怪怪的。我上小学的孩子回家来喊 “我要吃冰激凌今天，我没吃好长时间了”, 就是英文 “I want ice cream today. I have not eaten it for a long time.” 的直接翻译。
科技写作中，一般还是把主句先写出来，除非你想强调修饰的是条件。
Through scavenging free radicals, antioxidants play an important role in protecting against complex diseases.
宜改为： Antioxidants play an important role in protecting against complex diseases through scavenging free radicals.
In microbial fermentation, phosphorus is commonly the major growth-limiting nutrient.
宜改为： Phosphorus is commonly the major growth-limiting nutrient in microbial fermentation.
主动句中事情的执行者 (作者) 放在前面，有强调事情的执行者 (作者) 的意思, 而不是要研究的事物。被动句强调要研究的事物，这也是为什么科技论文中被动句用得比较多的原因之一。
We studied their effects on cell growth. 强调 We.
Their effects on cell growth were studied. 强调 Their effects.
6. 修饰词和被修饰词要邻近
科技写作要求严谨，明确为了严格定义一个事物，往往要加上限制性的修饰词或短句。比如描写实验用的mice时，一般不会只说 mice， 而是用类似 “NCI-H23 tumor bearing female athymic nude mice” 的描述。前面有5个修饰词来定义研究用的mice 这时一般把最窄的定义写在最前面，最广的定义写在后面。修饰语要靠近同被修饰的对象。因修饰语和被修饰的词被隔开，而造成意思混乱的情况很多。下面是一些例子。
Inhibition of Acid B on xanthine oxidase was also reported.
Inhibition of 后面应紧跟 xanthine oxidase , 而不是 Acid B, 隔开后句子就很难读。
宜改为： Inhibition of xanthine oxidase by Acid B was also reported.
The chelating activities for ferrous ion of the Acid B were assessed.
The chelating activities 后面应紧跟 Acid B , 而不是 ferrous ion.
宜改为： The chelating activities of the Acid B for ferrous ion were assessed. Reducing power represents the electron donating capacity, which may serve as a
significant indicator of potential antioxidant activity.
用 which 开头的修饰句，是要修饰 reducing power, 而不是修饰 electron donating capacity, 所以要紧跟在 reducing power 后面。
宜改为： Reducing power, which may serve as a significant indicator of potential antioxidant activity, represents the electron donating capacity. 或: Reducing power represents the electron donating capacity. It may serve as a significant indicator of potential antioxidant activity.
7. 主语和谓语在句子中的位置要靠近
要使句子的可读性强, 有两个因素特别需要注意。一是句子的长短要合适。 研究表明一个句子中有 13-20 个字时最合适阅读。太短的句子有零碎的感觉， 而太长的句子读起来有困难。二是主语和谓语动词要靠近，如果被隔开太远， 就会有被隔离的感觉，句子读起来就会比较困难，虽然从语法上来讲是可行的。这主要同人类大脑处理文字信息的过程和方式有关。当人们读到主语时，自然而然地期望知道主语后面的行动，也就是结果。在行动 (谓语) 出现之前，读者需要记住主语是什么，同时又要阅读和理解下面的文字，读起来很累。就像要屏住呼吸等待要发生的事情, 只有当谓语出现，知道了主题的行动后，才能呼出这口气。时间长了自然不舒服。
Lincomycin, one of the lincosamide antimicrobial agents which was first isolated more than fifty years ago , is used as a major antibiotic for the treatment of diseases caused by most Gram-positive bacteria.
宜改为： Lincomycin is one of the lincosamide antimicrobial agents which were first isolated more than fifty years ago. It is used as a major antibiotic for the treatment of diseases caused by most Gram-positive bacteria.
8. 名词作形容词
科技写作中经常会用名词来作为形容词使用，如 room temperature, university researchers. 当用一个 名词来修饰另一个名词时， 意义一般都很 清楚。但当三个名词 放 在一起， 或两个名词前再加一个形容词时， 就要小心。
有的情况下 , 3 个或 3 个 以上的名词放在一起，表达的意思很清楚，也是一种很简洁的表达方式。如: blood white cell number, prostate cancer patient, Beijing University medical school student. 但有时会有多种讲法. Top university researchers 可以是 researchers of (only) top university 也可以是 (all) university researchers who are top. 多个名词排在一起， 即使表达明确， 也给拥挤的感觉。应避免使用多个名词的修饰方式。最好的办法是用介词或其它方式来把他们分开, 以便清楚表达它们的修饰关系。多个名词罗列的情况经常发生，下面 多举一些例子。
H e wrote the quality control group reports.
宜改为： He wrote the reports of the quality control group.
The patient showed chronic liver disease symptoms.
宜改为： The patient showed symptoms of chronic liver disease.
The human brain oxygen level is quite high.
宜改为： The oxygen level in human brain is quite high.
Their specific inhibition producing effects on fat containing food intake were assessed.
宜改为： Their specific effects of inhibition on the intake of fat containing food were assessed.
The present investigation evaluated various specific drug sample combinations. 宜改为： The present investigation evaluated various combinations of specific drug samples
9. 句子的时态
科技论文中基本上只用现在时和过去时两种时态，有的作者偶尔会使用完成时。完成时一般只用于多次并一直在研究的情况，其他的时态用得很少。论文中的时态有它特定的意义，时态用来表明科研成果的认知程度。 当描述已发表的文献成果时，用现在时，因为已发表的成果被承认是事实。描述未发表的实验和结果时，用过去时，因为还没有得到承认，并且是写论文以前做的事情。由于科技论文中的时态的特定用法，写作中经常需要转换时态。一句话中都可能用两个时态。总起来说，Abstract中要讲述自己的实验和结论，要
用过去时。Introduction中要总结文献和问题, 以现在时为主，也用一些过去时。Methods 和 Results 都是讲自己的实验和结果，用过去时。而 Discussion中则需要根据描述文献还是自己的实验，需要交换使用现在时和过去时。
在引述文献结果时，过去发表的结论可以认为是已经被承认的事实，应该用现在时。但引述过去的实验时，特别是以作者为主语时，因是过去做的事情，应该用过去时。
Wang showed that the rate of growth is dependent on temperature.
Smith studied the growth rate and reported that it is dependent on temperature. 若作者不是主语, 而作者的研究是主语时，用现在时。
Investigation by Wang shows that the rate of growth is dependent on temperature.
当描述自己的实验和实验结果时， 应用过去时。因为是在写文章以前做的事情, 并且还没被接受为事实 ( 发表 ) .
We measured its plasma concentration and found that it was two times higher in obesity patients than in normal population.
讲述 table 或 figure 中显示的结果时，可以用现在时。
Table 4 shows that growth was dependent on temperature.
计算的结果和统计分析结果应该用现在时 .
The calculated value is significantly lower indicating most of the dissolved compound was degraded.
10. 主动句和被动句
许多人认为科技论文都应该用被动句，不要加入个性的成分。现在越来越多的杂志提倡使用主动句，因为主动句更简洁和明确。把 “ it is reported by the authors of this paper that” 改为 “ We reported that” 就显得更简要和直接。下面是个例子 :
In 2002 we reported the synthesis of anthramycin analogues and their DNA binding activities studied by gel electrophoresis.
但实验部分还是主要使用被动句 . 用 “The drug concentration was measured
by HPLC” 而一般不用 “ We measured the drug concentration by HPLC”.
11. 标点符号的使用
英文科技论文写作中经常使用的标点符号有逗号，句号和分号，冒号和问号使用的情况很少，而惊叹号几乎就不会被使用。现在分号使用的也逐渐减少,一般用句号取代。一篇论文中只是使用逗号和句号也是正常的。句号的使用比较明确,下面主要对逗号的使用作一些说明。逗号虽然很小，但要表达清楚你要传达的信息却离不开它。比如下面的例子，没有逗号时句子不好读。加逗号后，逗号放在不同的地方,意思完全不同 .
Although it was incubated at 50 o C for 24 hours no reaction occurred.
Although it was incubated at 50 o C for 24 hours, no reaction occurred.
Although it was incubated at 50 o C, for 24 hours no reaction occurred.
逗号是用来分开两个独立的句子，下面的句子是可以的 .
Ethanol is used to replace gasoline, and it is produced from corn.
下面的句子就不合适，因为逗号后面不是一个完整的句子 .
Ethanol is used to replace gasoline, and is produced from corn.
当一个长的语句出现在句子的前面时， 要用逗号分开。若语句不长, 不需 要停顿，也可以不用逗号。
During the process of solvent removal, some crystalline solid was formed. During the process precipitate was formed.
12. 数字的写法
科技论文离不开数字。数字的一种写法是用英文字，如 three, thirteen。另 一种是写阿拉伯数字。具体用哪种写法可参照以下几个简
单的规则
1 ) 少于 10 的整数用英文字， 大于 或等于 10 的数字用阿拉伯数字 . thee experiments
one assay
23 birds
6,500 miles
2 ) 有小数点和单位的数字用阿拉伯数字
1.2 hours
5 percent
3 am
3 ) 在句子开头的数字用英文字
英语的一个句子的开始是用大写字母来表明的。 如果是一个数字, 那就不能起到表示一个句子开始 的作用。所以不能用数字开始 一个句子。这时要把数字用英文字写出, 或 最好能修改句子， 不用数字开头。一个经常被使用的办法是把表示数量的数字放到括号中去 .
10 ml ethanol was added.
Ten ml ethanol was added.
Ethanol (10 ml) was added.
30 eggs were used daily during the study.
宜改为： During the study, 30 eggs were used daily.
4 ) 当两个数字前后并列出现时, 一个要用英文字 .
当两个数字前后并列出现时， 若都写成数字或文字， 容易产生混乱 . three eight-rat groups to: three 8-rats groups
3 8-rats groups to: three 8-rats groups
two 5-day study
12 two-engine airplanes
5)
0.25 gram
0.8 second
1.5 grams
3.45 seconds 但是零后面的单位用复数.
zero meters
0 meters
单位的缩写单数和复数是一样的 .
0.1 ml
15 ml
13. 冠词的使用
使用冠词是英语的特点 ， 中文没有相应字词。对 定冠词 the 和不定冠词 a 、 an 的使用 往往 掌握 不好 ， 最常见的是漏掉 .
There has been increase in loss of agricultural land.
宜改为： There has been an increase in the loss of agricultural land.
Stresses at various locations in crank are calculated by using sets of unit load cases applied to single throw FE model.
宜改为： Stresses at various locations in the crank are calculated by using sets of unit load cases applied to a single throw FE model.
再就是定冠词 the 用多了 .
The alcohol is produced by the fermentation of the grains like corn and wheat. 宜改为： Alcohol is produced by the fermentation of grains like corn and wheat. Alcohol 和 grains 都是泛指 , 不需要加定冠词 the.
除了是第一个字， 题目中的冠词不要大写 .
The Dependence of Crystal Growth on the Solvents.
14. 同位词的使用
写作中有时需要对新引述的事物或概念做简单解释和描述，但单写一个句子又会打断前后的连接。这时用同位词来解释是一个经常 使用的方式 .
The Hallervorden – Spatz syndrome, a neurological disorder associated with iron accumulation, has been linked to a decline in cysteine dioxygenase activity.
同位词应该同修饰的事物等位， 说明是什么 , 而不能用来解释要修饰的事 物的性质 . 下面句子中的同位词的使用就不合适 .
Penicillin, not stable in water , was developed during WWII.
15. 多余的用词
The supernatant was collected and concentrated in vacuum to evaporate the solvent.
Concentrate 就是 evaporate the solvent ， 后面的 to evaporate the solvent 是多余的.类似的把一些词的含义再次重复说明是最容易出现的多余用词.类似的 8PM in the evening, blue in color, small in size, in vivo animal models, in vitro cell cultures 都有多余用词的情况 .
The results of activities of tested compounds were listed in Table 1.
.中文中经常写作“实验结果”“ 活性检测结果”，但英文中“ 结果 ”是不需要翻译出来的 .
宜改为： The activities of tested compounds were listed in Table 1. 下面的例句中， their 就是 acid B and D ， 二者要去掉一个 .
The chemical mechanisms of their antioxidant activities of acid B and D were not well understood.
宜改为： The chemical mechanisms of the antioxidant activities of acid B and D were not well understood.
一些词组， 如 it should be mentioned, it should be pointed out, it was found, it ? 都是冗长和委婉地说法，应该直接说明 .
字的使用中特别注意事项
1. 用字要准确
每个科学术语都有其特定的含义, 使用要准确．比如微生物学中经常使用Medium, Broth 和 Culture三个词，但它们之间存在差别. Medium是培养基, 可以是液体也可以是固体；Broth是培养液, 只是液体; 而 Culture 是指细菌和培养液的混合物. 如果要从发酵罐中取样, 那取的样应该是Culture, 而不能用Medium或Broth. 化学中的量和浓度有明确定义, Mole和Molar就大不一样．Molar和Normal对有些是一样的, 对另些化合物则是不同的．物理学中的温
度、距离、时间等均有自己的严格定义．科研人员对自己专业的词一般都能较好的掌握, 但对一些普通词汇的使用常掌握不准．举几个简单例子:
比如, Promote 一般指职位的提升, 不能当Increase来使用.
Production was promoted by 16% in the new procedure.
宜改为: Production was increased by 16% in the new procedure.
再比如, Perform表示一个行动，而不指某个具体事物. 浓度不能Perform, 但测浓度可以用Perform.
The zinc concentration was performed.
宜改为: The zinc concentration was measured.或Measurement of the zinc concentration was performed.
2. 推理用语的使用
从实验观察和数据到结论的推理过程中，在事实和理论的关系上可能有从“同?一致”,“表示”， “证明”等不同的强弱关系，在选择用词上要合理. 英语中经常使用的词是is compatible with, imply, suggest, indicate, show, prove. 这基本上是一个从弱到强的顺序. 表示是个合理的解释, 不矛盾, 但可能还有其他的解释. 表示支持现在的结论， 这个结论比其它的更合理, 但不能 证明就是这个结论.
就更确定, 表示几乎就是这个结论了. 其他的可能性不大, 但还不是百分之百的证明. 表示完全肯定， 没有任何其他可能性了. 科研中很少有这种情况. 用 prove 要特别注意.
3. 用词要保持一致
论文从头到尾用字要保持一致.比如时间单位的分钟即可以全拼成minutes,也可以简写成min,二者都可以，但只能用一种写法. Figure或 Fig只用一种写法.数字的写法上，如果一个写成 fifteen, 另一个写成12也是不一致.修改论文稿件
时应特别注意用词的一致性.
4. 尽量少用简写
作者自己熟悉的简写，读者不一定知道，所以应尽量少用简写. 必需时, 宜于第一次出现全名时在其后用括号标出简写．比如Heat Shock Protein (HSP)、Multi Body Dynamics（MBD）. 至于广泛使用的简写, 如ml, AIDS 等可不用写出全名.
5. 不要用缩约语
正式地写作中, 不要使用如 didn't, don't, can't, haven't?.缩约语. 应该写完整形式, did not, do not, cannot (一个字), have not ?. .
6. 避免使用俚语
虽然非英语国家的作者不是很好区分什么是俚语，但还是要注意不要使用像 a lot, sort of, pretty good?的口头用语.
7. 经常使用， 但容易出现问题的字
Above
经常用来指前面提到过的，表示 “ 如前所述 , as discussed above” “ 前面的方法 , the above method” 等 . 但 above 不确定，用起来容易， 读起来不易明白, 容易造成表达不清。这时应把所指的事情明确地写出来。类似不明确的字还有 former, latter. 应避免使用
Adapt, adept, adopt Adapt 是动词 ， 适应 . Adept 是形容词 ， 熟练的 . Adopt 是动词 ， 采用 .
Affect, Effect, Impact
Affect 是动词，影响 (influence) 的意思 . 如 “ 温度对细胞生长的影响 , “Temperature affected the growth of cells”.
Effect 是名词，是结果 (result), 影响的意思。有时也可以作动词 , 招致 (bring about) 的意思 . 科技论文中很少使用 effect 的动词形式 .
Impact 当冲击，碰撞讲 . 如 “ Western popular culture has a huge impact on Asian society ”. 自然科学不同参数的相互影响一般不用 impact 来描写 , 用 affect 或 influence 更合适 .
Agree to, agree with
, giving consent. “I agree to a biopsy test”.
, in accord. “The results agree with our previous observation”.
Alternate, Alternative
Alternate 是交替的 ， 轮流的 . Alternative 是另外的 ， 选择的 . And
And 是一个非常有用的字 . 它是一个最被经常用到的连接词 , 可以连接 类似的词 , 词组或句子。用 and 连接的词 , 词组或句子是相关联但又各自独立的。当排列三个以上的词时，最后的一个词之前加 and . 其它的词后都加逗号 .
Pollution in the river affected the population of different animals, such as fishes, birds, and turtles.
And 之前也可以不加逗号 .
Pollution in the river affected the population of different animals, such as fishes, birds and turtles.
一般认为 and 之前加逗号是美国写法 ， 不加逗号是英国写法 .
用 and 连接句子时，若两个句子都很简单，中间可以不加逗号 .
One liter of water was added and the solution was left at 4 o C overnight. 但中间加个逗号也正确 .
One liter of water was added, and the solution was left at 4 o C overnight. 两个比较复杂的句子中间一定要加逗号，以便于阅读和理解 .
The assay was carried out by heating the sample in boiling water for two hours, and the volume of the assay solution was kept constant by adding water.
用 and 来开始一个句子也是可以的 . and 起到对一些相关和并列的描述来 连接的作用 .
AIDS drugs are effective to control the replication of HIV, but they cannot cure AIDS. And a vaccine for AIDS is still elusive. Therefore, education and prevention are the most effective weapons against AIDS for now.
用 and 连接两个独立的句子时, 可以在 and 之前加逗号，也可以不加逗号。但连接一个不完整的句子时 , 不能用逗号分开。
The sample was added to the testing solution, and allowed to react in a water bath at 37 ℃ for 10 min.
宜改为： The sample was added to the testing solution and allowed to react in a water bath at 37 ℃ for 10 min.
Apparently (apparent)
有 “ 明显的， obvious , clear ” 和 “ 貌似的， seeming ” 两种用法 . 具体是 哪 种讲法 , 句子的前后内容可能会有提示 . 在不能确定的情况下 , 应避免使用 , 选用 obvious 或 seeming 更好 .
Apparently 也是一样，选用 obviously 或 seeemingly .
Appear
Appear 有 ” 出现 , to come into view ” 和 ” 好象 , seem” 两种讲法 , 一般在科技论 文中 , 当 “ 好象 , seem” 的讲法用的要多些 .
After cooling down to room temperature, yellowish crystals appeared .
It appears that deformation of frogs in the Hui River is caused by pesticides. As
As 有很多不同的讲法，它有表示因果关系的用途，类似 because 和 since . 但 as 表示的因果关系最弱 ， since 在中间 ， because 的因果关系最明确 . 所以 不要用 as 来表示因果关系 . 用 because 或 since .
As 用来表示 “ 同样地 ”, “ 像 ? 一样 ”.
The genetically engineered apple tastes as good as the natural one.
As soon as the body temperature reached 39 o C, the child has to be sent to the emergency room.
也当 “ 在 ? 的时候 ， when ” 讲 .
As the snow started to melt, the team went back into the forest to collect samples.
Average, mean, median
Average 和 mean 都是平均的意思 , mean 是个数学用语 . Median 是一个系列 中的中间的那个值 .
2, 4, 8, 16, 32 average 和 mean 是 12.4, median 是 8.
Because, because of
用 because 来表示因果关系是最明确的 . Because 后面写句子 ， Because of 后面用名词 .
The tiger population deceased dramatically because their habitat was destroyed. The tiger population decreased dramatically because of loss of habitat.
For 和 since 表示的因果关系要弱些 , 用 since 时往往强调的是当时的情况， 时间，地点等 . 有中文的 “ 既然 ” 的意思 . As 表示的因果关系最弱 .
Since the weather is hot and humid, we decided to take a break.
Below
同 above 一样 ， 所指含糊，应避免使用 .
Beside, besides
Beside 是 “ 在 ? 旁边 ” ， besides 是 “ 除了 ? ”. Between, among
Between 是两个人或事之间 , among 是两个以上人或事之间 . But
同 and 一样 , but 是一个被经常使用的连接词 . 它连接的句子有对照和相反的 意思 .
在连接比较简单的两个句子，并不影响句子的流畅的时候， but 之前可以不加逗号 .
He felt better but did not fully recover after taking the medicine.
连接两个比较长的句子时候， but 前应加逗号，把两个句子分开 .
Scientists spent months to figure out why the satellite did not reach its orbit, but they never find the truth.
But 也可以放在句子的开头 .
For a long time people realize there has to be a natural ligand for the cannabinoid receptor. But its identity was only elucidated recently.
用逗号把 but 隔开是不对的 .
But , its identity was only elucidated recently.
Cannot
Cannot 是一个字 ， can not 应写成 cannot.
Case
Case 只是起到填充空间 ( filler) 的作用，没有实质意义 . “ in the case of ” 的词组 .
Compare with, compare to
Compare with 是比较的意思 ， 而 compare to 是比作的意思 .
It is often to compare the human brain with a computer.
The human brain is often compared to a black box.
Compose, consist , comprise
Compose 当 “ 组成 ， 构成 ” 讲 ， 是及物动词 . 一般用 “xxx ” 的形式 . 如 : An atom is composed of a nucleus and a defined number of electrons.
Consist 当 ” 有 ? 组成 ” 讲 ， 是 不及物动词 . 一般用 “xxx” 的形式 . 如 : An atom consists of a nucleus and a defined number of electrons.
Comprise 当 ” 包括 ” 讲 ， 也有 “ 有 ? 组成 ” 的意思 . 到底是什么用法 ， 很容易 弄不明白 ， 所以干脆不要用这个字 .
Continual, continuous
Continual 是经常发生的 ， continuous 是连续和不间断的 .
Correlated with, correlated to
Correlate with 是正确用法 ， correlate to 是不对的 . Related to 是正确 .
Different from, different than
事物之间不同用 different from ， 人物之间不同用 different than. Different from 不能写成 different than.
Due to
Due to 是 ” 应归于 ?” 或 ” 有 ? 引起 ” 的意思 后面要跟名词 ， 同 because of 不同 . 但 due to 表达的也有因果关系的意思 . 如果你不是很 确定 , 应避免使用 due to ， 用 because of 或 caused by . Equipment
单数和复数都是 equipment ， 没有 equipments 的写法 .
Few, a few
Few 是很少 , 强调没有多少 , 有否定的意思 . A few 也是很少 , 但强调有一 些, 虽然不多，有肯定的意思 . Few 形容可数名词 ， little 形容不可数名词 . Little , a little 的用法同 few, a few 类似 .
Flammable, inflammable, nonflammable
Flammable, inflammable 都是易燃的意思 . nonflammable 才是他们的反义词 .
Following
Following 是形容词 ， 表示 “ 接着的，下述的 ”.
The behavior of the mouse was carefully monitored in the following days. 它也可以是动词 follow 的名词形式 .
Following the flood, many wild lives found new habitant.
Minimal, trivial
Minimal 是最小的 , trivial 是轻微的 ， 不重要的 .
Percent, percentage , percentile
Percent 跟在数字后面 ， 以代替 % , 57 percent (57%). Percentage 是百分率 , percentage 不能同数字一起用 . 可以说 small percentage or large percentage . Percentile 是一个统计学用语 , 表示在 100 个分组中事物 出现的机率 . Proven
Proven 是形容词 ， proved 是过去式 .
Provided that
连接词 ， 假如 . Providing 是现在分词 .
Remainder, remaining
都可以当 ” 剩余 ” 讲 .
Since
有 “ 自从 ?” 表示时间的意思 ， 也可以用来表示因果关系 ， 见 because .
Subsequently, consequently
Subsequently 表示时间顺序， consequently 表示逻辑推理结果 .
Such as
一般用逗号从主句分开，当 such as 后面排列的名词只有 1-2 个时， 不影响 句子的流畅 ， 可以不用逗号分开 . 排列 的 事物和概念要相等 .
Heavy metals such as lead are especially toxic to children.
The river is heavily polluted with heavy metals, such as lead, mercury, and cadmium.
Than
用 than 来比较的两个对象要一致 .
Acid A has a lower pKa than Acid B.
The water content in sample A is higher than that in sample B.
有些词代表最终状态，不能进行比较. 一些这样的词有 full, absolute, complete, unique, extinct, permanent, universal, 等 .
That, which
That/which 经常用来引导修饰从句 . 如果修饰从句可以省略掉而不影响句 子的完整性，也就是非限制性从句 , 用 which, 并用逗号把修饰从句从主句分 开 .
The recovered dogs, which were treated with antibiotics, are released.
如果修饰从句不可以省略掉 , 也就是限制性从句 , 那就用 that ，并不用逗号 分开 .
Dogs that were treated with antibiotics recovered.
限制性从句和非限制性从句在句子中的作用有很大区别 . 第一句话中 ， 就是 指 “ recovered dogs ”, 没有别的狗 . 第二句表示除了 “ Dogs that were treated with antibiotics ” ， 还有其他的狗 .
Toward, towards
Toward, towards 的用法是一样的 美国用 toward , 英国用 towards . Use, using, utilize, employ
我们写作时经常会使用 using 这个字，但用 using 时经常会导致同主句的 主语名词不一致 ， 应避免使用 . 可用 with 或 by 取代 .
Using the reductive reaction, reducing power of VC was examined.
宜改为 : The reducing power of VC was examined with the reductive reaction. Utilize 是利用 , 有效使用的意思 , 同 use 不同 . 不能相互替代 . Employ 雇用人 , 使从事于 ?.
While
While 既可以用来做表示时间的连接词 ， “ 当 ? 的时候 ”. 也可以用来表示 转折和逻 辑的连接词 , 当 ” 然而，虽然，尽管 ” 讲 . 为避免含义不清 ， 用 when 或 although 取代更好.
句子的连接和信息的传承
即使每个句子的语法合理，用词准确，但也不能保证论文就通畅，文字只是信息传递和描述逻辑思维的工具，文字用不好，当然信息传递就会出问题，同时信息本身的传承，思维的逻辑性也很重要.文字上要把这个过程描述出来。使文章紧凑和连贯要注意两个方面：一是内容,也可以说信息，要连贯；二是用好连接词和连接用的副词。
信息或内容的衔接就是要求每个句子中的主题(主语)在前面的一个句子中要交代过，如果一个新的内容猛然间出现，就会打乱思绪，有不知为何的感觉。
There is increasing interest in natural antioxidant products for use as medicines and food additives. Vitamin C, vitamin E and carotenoids are some of these widely used natural antioxidants . Reactive oxygen species (ROS) including superpxide anion
radical, hydroxyl radical and hydrogen peroxide, are generated under physiological and pathological stresses in human body.
这个例子中，第一句和第二句都与 natural antioxidant有关，但第三句出现了reactive oxygen species,同前面的内容没什么关系,这时第三句同前面的传承上出现了断离.下面的改动中加了个连接句子，把 natural antioxidant 和 reactive oxygen species 连 接了起来 . There is increasing interest in natural antioxidant products for use as medicines and food additives. Vitamin C, vitamin E and carotenoids are some of these widely used natural antioxidants . Antioxidants played an important role in lowering oxidative stresses caused by reactive oxygen species (ROS). ROS including superpxide anion radical, hydroxyl radical and hydrogen peroxide are generated under physiological and pathological stresses in human body.
从一个状况到另一个不相关的状况 时 ， 经常 用in addition to 的句子衔接 .
Oxygenases catalyze the incorporation of a molecule of oxygen (O 2 ) into the substrate. They catalyze the initial and rate-limiting step of L - Trp catabolism in the kynurenine ( Kyn ) pathway. ……….. In addition to its role as a L - Trp-catabolizing enzyme, IDO is involved in the immuno -regulating system………
科技论文有很强的推理特性 .要表达一个思维过程，思想之间的传承和衔接要紧密,合理.思维是用句子表达出来的，这样句子之间的衔接和关系就特别重要 .句子的衔接可以通过连接词，短句，或一个整句.衔接的作用就是把前后的思想贯穿起来，从而达到说明,推理,或讨论的目的 .
句子可以分为简单句和复杂句.复杂句中的短语之间需要用连接词和副词来连接。同时句子之间的传乘也需要使用连接词和副词 . And, but, or, for, nor, yet, .
除此之外，科技写作中经常使用一些连接副词，如 also, however, moreover, furthermore, therefore, otherwise, consequently, indeed, similarly, finally, likewise, then, hence, nevertheless, thus.
当用连接副词来连接两个独立的句子时，一般语法书中都注明第一个句子后加分号，连接词后加逗号.但现代杂志论文中往往在第一个句子后加句号,而不用分号，两种写法都是可以接受的 .
We quantified the extent of forest damage in the region; moreover , we attempted to explain why trees died.
We quantified the extent of forest damage in the region. Moreover , we attempted to explain why trees died.
It was rained; however , the drought persisted.
It was rained. However , the drought persisted.