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能否正确运用介词、冠词和单复数关系到论文的英文表达是否准确、规范，之前已经总结过介词和冠词的使用要点：

介词选择经验汇总

冠词使用的几个简单原则 — 覆盖常见情况

今天来谈谈单复数的问题，我们在论文润色修改中发现在遇到以下情况时容易出现单复数误用。

1. 不可数名词或集合名词

research是不可数名词，一般不加s，相应的谓语动词用单数形式。

Much research has demonstrated that …

studies是可数名词，可以加s.

Manystudies havedemonstrated that …

literature表示多篇文献的集合，一般不加s，相应的谓语动词用单数形式。

The literature was searched for articles.

content 作含量讲时是不可数名词，不加s；作内容（物）讲时是可数名词，可加s：

High-fat diet increased the content of cholesterol and triglycerides in the liver.

We tried to detect DNA fragments derived from maize in the intestinalcontents of pigs.

expression也是在不同的情况下可用作不可数或可数名词，但在论文中表示“表达水平”的时候是不可数名词：

The primary aim of this study was to characterize the mRNA and protein expression of Pgp, MRP1, MRP2, and CYP3A4 in human intestinal segments from human jejunum, ileum, and colon.

progress是不可数名词，一般不加s，相应的谓语动词用单数形式：

Much progresshas been made recently in understanding the molecular mechanisms of the cell-extracellular matrix interactions.

advance是可数名词，可以加s：

The past few years have witnessed remarkable advances in these areas.

efficacy作为不可数名词，一般不加s，前面也不加a，这一点和effect不一样：

Intravenous pamidronate has good efficacy for the treatment of ankylosing spondylitis.

Carbamazepine has a good effect on muscle stiffness and myokymia.

evidence是不可数名词，一般不加s，前面不用加a，相应的谓语动词用单数形式：

Here we provide evidence that these excitations appear in the phase with an incommensurate magnetic structure of the manganese spins.

Recent evidence suggests that such low-titer Wolbachia infections within arthropod hosts are more common than previously thought.

support是不可数名词，一般用单数形式，前面不用加a：

These results provide further support for the hypothesis that some forms of inflammatory bowel disease may result from impaired mucosal innate immunity.

staff是集合名词，表示全体职员，后面一般不加s，如强调整体，谓语动词用单数，如强调其成员，谓语动词用复数。

The staff were aware of the occupational exposure to hazards.

The unit is currently operating as a teaching facility with a staff of residents, attending staff, and consultants.

一般来说，staff前面如果有数词，后面要加个members之类的词，比如：

Four hundred staff members responded to the written survey.

或

Four hundred members of staff responded to the written survey.

但是staff前面直接加数词的情况也有，所以这一点并不是很严格：

Twenty-seven senior orthopaedic staff were then assessed by audiometry.

需要注意的是，我们有时也可以见到staffs，这个时候并非指多个职员，而是指好几批职员，比如：

Our experience supports that collaboration between staffs of laboratories and medical departments is essential to avoid mistaken diagnosis.

类似集合名词词还有：personnel、faculty、audience等，使用方法和staff相似。

2. 表示一种指标

按通常的理解，应该是sizes of lesions，因为有多个lesions，所以有多个sizes。

但实际上，size of lesions很常见，比如：

decrease in the size of lesions

change in the size of lesions

difference in the size of lesions

We evaluated the number and size of lesions.

这里的size是一项指标，所以不用加s，类似的例子还有：difference in the type of lesions.

根据不同胎龄（分组）一般不写成：according to different gestational ages，而是写成：according to the gestational age.

这里，according to后面跟的是一个分组指标，而不是具体的年龄，所以用单数。

类似的，一般不写成：There was no significant difference in glomerular filtration rates between the two groups；

而是：There was no significant difference in glomerular filtration rate between the two groups.

在这里，reduction后面是否加s，决定于reduction后面有几个指标，如果只有一个指标，那么即使前面有多组，后面也不加s，比如：

Both groups showed a significant reduction in scratching.

如果后面有多个指标，即使前面只有一个组，reduction后面也加s，比如：

The intervention group had significant reductions in fasting blood glucose, glycosylated hemoglobin, total cholesterol, and low-density lipoprotein cholesterol.

把reduction替换成decrease、increase和change也是一样的道理。

3. 名词修饰名词，前面的名词多用单数

比如mice在model的前面时，一般是mouse model，而不是mice model，如果用mice则放在model后面。

一般来讲，比较常见的表达有以下几种：

名词1修饰名词2，名词1一般用单数，但也不是绝对，比如：

larvae samples比larva samples更常见。

另外，还有常见的sports meeting。

4. 表示某一类

英文中可数名词泛指一般事物时常用单数形式，比如：

A retrovirus is a type of RNA virus that inserts a copy of its genome into the DNA of a host cell ....

The rodent is a nocturnal mammal thatinhabits …

当然，也可以用复数：

rodents are small animals with robustbodies …

5. 有时单复数和冠词相关

单复数的选择有时和冠词相关，比如以下两种表达都正确：

也就是说当control前面有the时，后面的group用单数形式。

6. 有时主语含多个名词，谓语动词用单数

7. 其他

more than one + 单数名词

More than one patient was treated in the resuscitative room.

one and a half + 复数名词

One and a half yearshave elapsed since complete healing.

one or more + 复数名词

One or more criteria were not met.

many a + 单数名词

Many a patient comes complaining of heat in some part of the body.

every后面接多个名词时，谓语动词用单数形式。

Every mother and child has a right to health and well-being.

8. 名词单复数和动词单复数的关系

一般来说，名词是单数，相应的谓语动词就是单数，名词是复数，相应的谓语动词就是复数。

但也有例外。

有时名词是单数，相应的谓语动词是复数，比如上面说的集合名词 staff，当它强调其成员时，谓语动词用复数。

有时名词是复数，但被视为一个整体，所以相应的谓语动词仍用单数，比如 ：

One hundred million years is enough for the origin of life on the earth.