词汇和语法是制约雅思写作成绩提升的两个重要部分，因为在写作的四项评分标准中，这两项指标占据了半壁江山。词汇需要我们平时的积累，今天就来说说语法部分，大家可能因为它的单调枯燥会忽略它，下面就从句子结构层面展开探讨。

　　1、 串句

　　串句是不用连词或标点而把两个(或以上)独立的句子串在一起的错误表达。有些串句是不用任何标点间隔两个甚至更多的句子;有些串句是在该用句号时滥用逗号，忽略了逗号本身没有连接句子功能的原则。

　　No one can deny the fact that air pollution is an extremely serious problem the city authorities should take strong measures to deal with it。

　　There is a general discussion there days over education in many colleges and institutes, one of the questions under debate is whether education is a lifetime study。

　　修改和避免串句错误的常见方法：

　　①用句号把原句分成两个独立的句子;

　　②用连词连接两个句子;

　　③用分号连接两个句子。

　　如：

　　No one can deny the fact that air pollution is an extremely serious problem, so the city authorities should take strong measures to deal with it。

　　There is a general discussion there days over education in many colleges and institutes; one of the questions under debate is whether education is a lifetime study。

　　2、 破句

　　破句是把不完整的句子当作独立的句子来写时发生的错误。

　　以下是常见的几个破句的例子：

　　Students should be encouraged to take part-time job. Because it will benefit students and their family, even the society as a whole。

　　点评：从属连词引起的破句。常见的从属连词有after,unless, even if, even though ,since , before , when (whenever)，because, if, who(whoever)，while, as (as if )， which(whichever)， although , so that, where(wherever)， until, that等。像because这样的从属连词开头的从句是不能单独存在的，它依赖于另一个句子方能使意义完整，也就是说单独的从句本身就是破句。

　　修改后：Students should be encouraged to take part-time job because it will benefit students and their family, even the society as a whole。

　　A large number of people think that they had completed their education when they finished their schooling. Not realizing that a person’s education is a most important aspect of his life。

　　点评：分词引起的破句。当分词出现在一个短语或句子的开头时常常会产生破句，而这样的破句往往缺少主语或谓语动词的一部分。

　　修改后：A large number of people think that they had completed their education when they finished their schooling. They fail to realize that a person’s education is a most important aspect of his life。

　　International travel has given rise to large numbers of employment opportunities. For example, retail, hospitality and transportation。

　　点评：增加细节引起的破句。往往以下面的词语开头：for example, also, except, such as, including, especially, among, like。

　　修改后：International travel has given rise to large numbers of employment opportunities in retail, hospitality and transportation。

　　Many sociologists point out that rural emigrants are putting pressure on population control. And also threatening to take already scarce city jobs。

　　点评：缺少主语的破句。用and之类连词打头的短语或句子居多，可通过使破句依附于前面的句子或加上主语的方式进行更正。

　　修改后：Many sociologists point out that rural emigrants are putting pressure on population control and also threatening to take already scarce city jobs。

　　3、 错误的平行结构

　　所谓平行结构，就是指两个(或以上)意思并列的成份(包括单词、词组、从句和句子)在写作时要用同等的语法形式表达，并保证逻辑上的一致，否则就破坏了其平行结构。

　　①错误的并列

　　In order to attract tourists, a lot of artificial facilities have been built and which have certain unfavorable effects on the environment。

　　点评：and who/and which 结构是考生所犯的错误中最常见但最严重的一种，因为它导致从句与主句间一种不合逻辑的关系。

　　修改后：In order to attract tourists, a lot of artificial facilities have been built, which have certain unfavorable effects on the environment。

　　②一系列平行结构上的不正确使用

　　Many people choose air transportation because it is fast, offers convenience and it is not very expensive。

　　点评：当词或词组被放在一个系列时，它们在意义上和结构上必须都是平行的。

　　修改后：Many people choose air transportation because it is fast, convenient and inexpensive。

　　③错误的省略

　　It is commonly thought that modern technology has and will dramatically change our society。

　　点评：这种错误在have/ has ,will, shall结构中较为常见。

　　修改后：It is commonly thought that modern technology has dramatically changed our society and it will continue。

　　④逻辑上的不一致

　　The percentage of cancerous persons among smokers is significantly higher than non-smokers。

　　点评：使用than或as的比较形式，较容易出现不合逻辑的现象。

　　修改后：The percentage of cancerous persons among smokers is significantly higher than that among non-smokers。

　　雅思写作所运用的语法知识基本都是中学所学的语法内容，因此对于广大考生，特别是语言基础相对薄弱的考生，建议先对这些基础语法内容进行系统的复习，然后一定要动笔练习，通过老师的批改或者学习软件，发现自己语法方面的漏洞，及时差漏补缺，做到表达正确并非难事。