在这一系列的第三部分，我想讲讲复数单词（尤其是拉丁复数词），组成一个系列的单词，以及 “分别”、“连续逗号“（也被称为牛津逗号）的使用。与第一和第二部分中一样，例子将用粗体表示。

中文和日文（可能还有韩文和其他基于中文的语言）中，不会在复数单词之后添加一个额外的“S”。作为编辑，每次我看到作者没有在复数词之后加“S”或“ES”，我马上就知道这些作者需要在其他方面提升英文水平。其实很简单。作者在写作时应该记住需要考虑用到复数单词，而且确保使用的是正确的复数形式。这个例句就存在错误：Many author should remember to use the plural form of word. 也就是说，这应该使用“authors” 和 “words”。

但是，英文中常常有例外。一些单词的复数形式不（或很少）需要一个额外的“s”。我们称之为“集体名词”。使用集体名词时，一组事物被当作一个大的事物。最好的例子是“家具”这个词。英语为母语的人可能会说a single piece of furniture or many pieces of furniture（单个的家具或许多家具），但是却不会使用“furnitures”这个词，因为在一个房子里的所有的家具被认为是一个集体，是一个事物。这里有一些正确的单数和复数形式的例子（集体名词的单数和复数拼写相同）：advice, content, evidence, infrastructure, research, seaweed, shrimp, slang, stuff。这些集体名词，我们很少（甚至从来不）对它们添加一个额外的“s”如：advices, contents (有时会用), evidences, infrastructures, researches, seaweeds, shrimps, slangs, stuffs。

那些了解拉丁语的语言学家们，可能会告诉你为什么要给那些来自于拉丁语的英语单词创造复数形式。我们在科学界坚持用拉丁语的原因很简单。简而言之，很久以前一群大多是欧洲人的科学家想选择一门语言用于科学界，英国人想用英语，法国人想用法语，德国人想用德语；最后他们唯一都赞同的一门语言是他们都没有使用的拉丁语。当使用来自拉丁语的单词时，以不同的方式结尾的单词变成复数时拼写也不一样。看一下这些类似的单数和复数单词：apex and index; herbarium and medium; lamella and stoma; genus and species。它们的复数形式是相似的，有一定的规律，但并非完全一致：apices and indices; herbaria and media; lamellae and stomata; genera and species。当你看到一个看起来是来源于拉丁语的词的时候，例如以-ex或-ium结尾的名词，请记得查阅字典以获取正确的拉丁形式。

最后，我想讨论在一个系列中使用的单词以及“respectively”这个词。要列出一系列词语可以采用两种方式。在“and”这个单词前的逗号叫做“系列逗号”或者“牛津逗号”，这两个术语的意思是一样的。下面是这两种方法：不使用系列逗号，我可以写“dogs, cats and mice.” ；使用系列逗号，则是“dogs, cats, and mice.”。 尽管很多作家，包括英语为母语的人，不使用系列逗号，但是使用它却是很重要的。为什么呢？因为它可以避免意义混淆。

例如，看一下这些句子，第一个有系列逗号，第二个没有：“The group met with two clowns, Bill, and Tom””和“The group met with two clowns, Bill and Tom.”在第一句中，小组会见了四个人，其中两人是小丑。在第二个句子中，小组会见了两人，两人都是小丑，他们的名字是Bill和Tom。在科技写作中，缺少系列逗号有时会改变你的句子的意思。

同样，让我们看看三种动物。我们将使用系列逗号来确保意义清楚，然后再介绍“respectively ”这个单词。看看这一系列的单词（你可能会注意到series和serial这两个单词是相关的，拼写方式相似）：dogs, cats, and mice。我们现在有三组动物，而不是将“cats and mice”分为一个组，因为我们使用系列逗号来表明了这里有三个组，而不是两个组。他们吃什么? Dogs, cats, and mice eat meat, mice, and grain, respectively. 使用respectively来连接两组单词。也就是，dogs eat meat, cats eat mice, and mice eat grain.在这最后这个例句中，我们不使用“respectively”这个词，因为哪些动物吃哪些食物是非常清楚的。

也就是说，使用“respectively”连接两个系列的单词。这里有一个例子，作者可以使用“respectively ”这个词来节省空间。

The study site, a rock outcrop surrounded by forest, had a mean annual temperature of 13°C, a mean annual precipitation of 40%, and a mean annual wind speed of 2 m s₋₁.

在这个例子中,我们使用了一个同位语(the study site = a rock outcrop surrounded by forest， 因此后面的短语是一个同位语)。然而，你会发现“mean annual”被重复三次。我们可以通过使用”respectively“这个词来缩短这一系列。

The study site, a rock outcrop surrounded by forest, had a mean annual temperature, precipitation, and humidity of 13°C, 40%, and 2 m s₋₁, respectively.

比较一下这两个句子。哪一个更短？我们用“respectively”这个词来保持句子简短，使他们更容易理解。

最后，我们想用一个错误的例子来总结一下。结一下。In this paragraph we will try to do everything wrong, mis-using the little things of capitalization, punctuation, and spacing, using simsun fonts with english, creating run-on sentences like this one that never seems to end, failing to use semicolons, using informal English, starting sentences with “And,” failing to use commas with appositives, failing to use numbers correctly, misplacing time units and really messing up by not using the serial comma.  You’ve just had your example of a run-on sentence the sentence before this one.  And the sentence before this sentence had an appositive that didn’t have a comma to set it off.  And the series of words didn’t use the serial or Oxford comma and this run-on sentence fails to use a semi-colon and uses the word “and” too often at least 4 times and is too long.  Today we have made numerous errors in this paragraph（so if you were an editor and you receive a document that looks like this one you will send it back to the author).如果你是一个编辑收到这样的文章，肯定会直接发回给作者。

你还会对作者说，“找一个英语母语的人帮助你改写英语吧！”或者，你可以通过注意我们之前讨论的各种问题，来提高你的英语！

此短文由LetPub美国总公司的科学编辑撰写，英文原文如下：

How to Avoid Common Errors with English:Part III

In the third part of this series I would like to discuss the use of plural words (especially Latin plural words), the use of words in a series (including use of the word “respectively” and the “serial comma” which is also known as the Oxford comma).  As we did in Parts I and II, bold text will indicate examples.

Chinese and Japanese (and probably Korean and other languages based on Chinese) do not use an added “S” to form plural words.  As an editor, when I see a writer failing to add an “S” or “ES” to plural words, I instantly know the authors need to work on improving their English in other ways.  My point is simple.  Authors should remember to think about plural words as they write and make sure to use the correct plural forms.  Here is a sentence that fails to do that: Many author should remember to use the plural form of word.  That is, this should talk about “authors” and “words.”

However, English is a language of exceptions.  Some plural forms of words never (or rarely) take an added “s.” We call these “collective nouns.”  With collective nouns, groups of things are considered to be one large thing.  The best example is the word “furniture.”  Native speakers might talk of a single piece of furniture or many pieces of furniture.  The word “furnitures” is never used because all the furniture in one house is thought of collectively, as one thing.  Here are some examples of correct singular and plural forms (both are spelled the same way for collective nouns): advice, content, evidence, infrastructure, research, seaweed, shrimp, slang, stuff.  For collective nouns, we rarely (or never) an added “s” with these nouns: advices, contents (sometimes is used), evidences, infrastructures, researches, seaweeds, shrimps, slangs, stuffs.

A linguist who knows Latin could probably give you the reasoning behind creating plural forms of English words that are taken from Latin.  We are stuck with Latin in science for a simple reason.  In short, long ago a bunch of mostly European scientists wanted to choose a language for use in science.  The English wanted to use English, the French wanted to use French, the Germans wanted to use German; the only language they could agree on was one that none of them used, Latin.  When using words that come from Latin, different endings of plurals are spelled in different ways.  Look at the singular and plurals of these similar groups of words: apex and index; herbarium and medium; lamella and stoma; genus and species.  The plurals are similar, with some patterns, but are not completely consistent: apices and indices; herbaria and media; lamellae and stomata; genera and species.  When you see a word that appears to have come from Latin, such as nouns ending in -ex or -ium, remember to check a dictionary to get the correct Latin form.

Lastly, I’d like to discuss words in a series and the word “respectively.”  Two methods can be used to list words in a series.  The comma before the word “and” is called the “serial comma” or the “Oxford comma;” both terms mean the same thing.  Here are the two methods. Without the serial comma, I could write, “dogs, cats and mice.”  With the serial comma, this becomes “dogs, cats, and mice.”  While many writers, including native speakers, do not use the serial comma, it can be important to use it.  Why?  It can help you avoid confusion.  

For example, look at these sentences, one with the serial comma, the second without it: “The group met with two clowns, Bill, and Tom” and “The group met with two clowns, Bill and Tom.”  In the first sentence, the group met with four people and two of those people were clowns.  In the second sentence, the group met with two people who were both clowns, the clowns named Bill and Tom.  In scientific writing, the lack of a serial comma can sometimes change the meaning of your sentence.

Similarly, let’s look at three animals.  We will use the serial comma to make things perfectly clear and then introduce the word “respectively.”  Look at this series of words (you might note that the words series and serial are related and spelled in similar ways): dogs, cats, and mice.  We now have three groups of animals, and we are not grouping “cats and mice” as one group because we used the serial comma to make it clear we have three groups and not two.  What do they eat? Dogs, cats, and mice eat meat, mice, and grain, respectively.  When you use the word “respectively” you are connecting two groups of words.  That is, dogs eat meat, cats eat mice, and mice eat grain.  In this last example, we do not use the word “respectively” because it is very clear which animal is eating which food.

That is, use “respectively” to connect two series of words.  Here’s an example of a way that a writer can save space by using the word respectively.

The study site, a rock outcrop surrounded by forest, had a mean annual temperature of 13°C, a mean annual precipitation of 40%, and a mean annual wind speed of 2 m s₋₁.

In this example, we’ve included an appositive (the study site = a rock outcrop surrounded by forest, so the latter phrase is an appositive).  However, you will notice the words “mean annual” are repeated three times.  We can shorten this series of words by using the word “respectively.”

The study site, a rock outcrop surrounded by forest, had a mean annual temperature, precipitation, and humidity of 13°C, 40%, and 2 m s₋₁, respectively.

Compare the two sentences.  Which one is shorter?  We use the word “respectively” to keep our sentences short and make them easier to understand.

Lastly, we would like to conclude with a bad example.  In this paragraph we will try to do everything wrong, mis-using the little things of capitalization, punctuation, and spacing, using simsun fonts with english, creating run-on sentences like this one that never seems to end, failing to use semicolons, using informal English, starting sentences with “And,” failing to use commas with appositives, failing to use numbers correctly, misplacing time units and really messing up by not using the serial comma.  You’ve just had your example of a run-on sentence the sentence before this one.  And the sentence before this sentence had an appositive that didn’t have a comma to set it off.  And the series of words didn’t use the serial or Oxford comma and this run-on sentence fails to use a semi-colon and uses the word “and” too often at least 4 times and is too long.  Today we have made numerous errors in this paragraph（so if you were an editor and you receive a document that looks like this one you will send it back to the author).

You would tell that author, “Find a native speaker to help with your use of English.”  Or, you can concentrate on the things we’ve discussed and improve your use of English!

（此文由LetPub编辑原创，转载请注明本文来自LetPub中文官网：www.letpub.com.cn/index.php?page=sci_writing_53）