一、 复合句的种类
英语的复合句一般分为三大类型：名词性从句、形容词性从句和副词性从句。
(一) 名词性从句
在整个复合句中起名词作用，充当主语、宾语、表语和同位语等的各种从句，统称为名词性从句。名词性从句主要有以下几种：
1. that 引导的从句 e.g. It is reported that one third of Guangzhou citizens plan to buy a private car. (据报道，三分之一的广州市民打算购买私家车。)
2. whether/if 引导的从句 e.g. Whether motorcycles should be banned in Guangzhou has become an issue of controversy.(广州是否禁摩托车成了有争议的话题。)
3. how/why/when/where引导的从句 e.g. This essay aims to explore why so many white collar workers suffer from insomnia. (本文将探讨为什么这么多白领失眠的原因。)
4. who/whom/whose/what/which引导的从句 e.g. Who should be responsible for the environmental degradation is still unknown.(谁对环境恶化负责还不清楚。)
(二) 形容词性从句
具有形容词功能，在复合句中做定语的从句被称之为形容词性从句或定语从句。被修饰的名词、词组或代词被称为先行词。形容词性从句分为两种类型：
(1)由关系代词 who, whom, whose, that, which, as引导的从句。 例如: People who are strongly against human cloning claim that it is immoral and unethical. (强烈反对克隆人的人们认为这样做不道德和不合伦理)
(2)由关系副词when, where, why引导的从句。例如: I would like to analyze the reasons why a growing number of teenagers are addicted to gambling.(我将分析为什么越来越多的青少年沉迷于赌博的原因。)
(三) 副词性从句
副词性从句也称为状语从句，主要用来修饰主句或者主句的谓语。大致分为九大类，分别表示时间、地点、原因、目的、结果、条件、让步、比较和方式。
(1)时间状语从句 e.g. When everyone is fully aware of the severity of fresh water scarcity and takes effective measures, I am convinced that we will tackle this problem constructively.(当每个人充分意识到淡水短缺的严重性，并采取有效措施，我相信我们一定能妥善解决好这个问题。)
(2) 地点状语从句 e.g. Where there is smoke, there is fire.(无风不起浪)
(3) 原因状语从句 e.g. Pets should be forbidden because they may spread diseases and damage the cityscape.(应该禁止饲养宠物，因为它们可能会传播疾病和有损市容。)
(4) 目的状语从句 e.g. Old people should be encouraged to live in a nursing house so that they can enjoy professional care and first-rate facilities. (应当鼓励老人到敬老院居住，这样他们可以享受到专业的照料和一流的设施。)
(5) 结果状语从句 e.g. Some government officials fail to recognize the potential hazards of improper waste disposal, so that the environment in some cities is deteriorating.(一些政府官员未能认识到垃圾处理不当带来的潜在危害，因此一些城市的环境不断恶化。)
(6) 条件状语从句 e.g. If we continue to overlook the increasing waste in Guangzhou, it is likely that Guangzhou will become a huge landfill site sooner or later.(如果我们继续无视广州日益增多的垃圾，有可能不久的将来广州将成为巨大的垃圾填埋场。)
(7)让步状语从句 e.g. While I admit that smoking has some side-effects, I still feel that it is ridiculous to ban smoking in public places.(虽然我承认吸烟有副作用，我依然觉得公共场所禁烟是荒唐的。)
(8) 比较状语从句 e.g. Red is two times as much as Blue.(红色是蓝色的两倍。)
(9) 方式状语从句 e.g. Just as we protect less able human beings, so we should safeguard the welfare of other weaker species.(正如我们保护弱者一样，我们也应该保护弱势物种的福利。)
二、怎样高效运用复合句写好引言段
Well begun is half done是大家耳熟能详的英语谚语。也就是说，一个漂亮的开头，往往是文章写作成功的一半。尤其在雅思和新托福写作考试中，好的开头往往能够在瞬间吸引考官眼球，留下良好的第一印象。那么，我们怎样才能写漂亮的引言段呢?首先，我们要做到开门见山，明确写作话题和目的。怎样才能做到开门见山?我们可以采用以下几种方式：
1. 采用统计数字引出话题，把问题呈现在读者面前;
2. 提出有争议性的问题，激发读者兴趣，使其积极参与讨论;
3. 以新颖的观点，吸引读者注意力;
4. 呈现该话题正反方的观点;
5. 引用名人名言、谚语等作为文章的开头;
6. 对将要讨论的话题进行定义。
其次，要善于运用复合句，从而使引言段简洁明了，开宗明义。下面我们将探讨雅思与新托福各种题材和体裁文章引言段的写作方法。
(一) 引用数据呈现讨论的话题，说明问题的严重性或者重要性，引起读者的关注。
下面我们结合几道雅思和新托福作文话题进行实战演练。
我们在写关于体罚的话题文章时，可以这样开头：It is reported that a boy in Zhuhai was beaten to death by his father on Father’ Day. Ample evidence also shows that children who are frequently abused by their parents or teachers tend to be introverted, pessimistic, indifferent and even world-weary. Recently, there has arisen a fierce argument on whether corporal punishment should be abolished. Teachers, parents and experts take diverse attitudes towards this issue.(据报道，在父亲节那天，珠海有个小男孩被老爸揍死了。充分的证据也显示，经常遭父母或老师虐待的小孩往往比较内向、悲观、冷漠甚至厌世。近来，关于是否应该废除体罚出现了一场激烈的争论，老师、家长和专家各执一词。)
而我们在写关于该不该禁烟的话题时，可以这样开头：A recent study conducted by Zhongshan University has found that the number of smokers has been increasing sharply over the past five years. Research findings also reveal that the incidence of smoking-related conditions has soared. As a result, the ban on smoking has been in the spotlight. (中山大学最近做的一个研究表明，在过去五年里，吸烟者人数急剧上升。研究结果同时显示，吸烟导致的疾病发病率也急剧增长。因此，禁烟成了个热点话题。)