好的英语句子应该是结构意思正确完整，连贯流畅，言简意赅。但是如果一篇文章中所有的句子都是结构单一(以主语开头，采用"主-谓-宾"或"主-谓-表"的结构)、长短均等的话，句子写得再好，文章也是单调呆板，缺乏生气。
一、 句子开头多样化
写作时最常见的是用名词或代词构成的主语作为句子的开头。除了主语外，句子中还有以下几种成分可以作为句子的开头。
1. 以同位语作为句子的开头。试比较下列两个句子：
A. Xiao Wang, our monitor，will attend the meeting.
B. Our monitor, Xiao Wang, will attend the meeting.
句A以主语Xiao Wang开头，句B以同位语Our monitor开头。
2. 以单个修饰语作为句子的开头。
这个修饰语可以是形容词、分词或副词。试比较下面几组句子：
A. She is young and ambitious, she works hard to get the job.
B. Young and ambitious, she works hard to get the job.
句A以主语She开头，句B以形容词短语Young and ambitious开头。
C. The girl entered the room gracefully.
D. Gracefully, the girl entered the room.
句C以主语The girl开头，句D以副词Gracefully开头。
E. The students reached the top of the mountain exhausted.
F. Exhausted, the students reached the top of the mountain.
句E以主语The students开头，句F以过去分词Exhausted开头。
3. 以短语修饰语作为句子的开头。
短语修饰语可以是介词短语、不定式短语、分词短语以及独立主格结构。试比较下列各组句子：
A. A beautiful girl stood in front of me.
B. In front of me stood a beautiful girl.
句A以主语A beautiful girl开头，句B以介词短语In front of开头。
C. The students worked hard to pass the exam.
D. To pass the exam, the students worked hard.
句C以主语 The students开头，句 D以不定式短语 To pass the exam开头。
E. He was confused about the problem and went to ask for his teacher.
F. Confused about the problem, he went to ask for his teacher.
句E以主语He开头，句 F以过去分词短语 Confused about开头。
G. You may go home after you finish your homework.
H. Your homework finished, you may go home.
句G以主语 You开头，句H以独立主格结构 Your homework finished开头。
4. 用从句作为句子的开始。试比较下列句子：
A. I will attend your lecture if I am free.
B. If I am free, I will attend your lecture.
C. We all know she is famous.
D. That she is famous is known to us all.
句A和句C以主语开始，句B和句D以从句开始。
值得注意的是句子的开头与句子所需强调的意义密切相关。改变词序有时会导致句子意义的细微变化。因此，在特定的上下文中决定是否改变某一句子的词序时，不仅要考虑我们所要表达的意思(如为了强调句子中的某个成分，将正常语序中较晚出现的成分移到句首)，还要考虑是否有利于上下文的衔接过渡以及句子是否均衡等。
二、句式的多样化
句式多样化是对一篇好的文章的基本要求。要做到这一点，首先要对英语句子有充分的了解。英语句子种类很多，句法结构丰富多彩。通常可以按照以下标准对英语句子进行分类：
1. 根据使用目的的不同，将句子分为陈述句，疑问句，祈使句和感叹句。
(1) 陈述句说明一个事实或是陈述说话人的看法。例如：
A. He must have finished his homework.
B. She is a diligent student.
(2)疑问句提出问题。例如：
A. Does she know English?
B. What did you do last night?
(3)祈使句用来表示请求，命令，叮嘱，邀请，劝告等。例如：
A. Have a cup of tea.
B. Don't smoke.
(4)感叹句表示说话时的惊讶，喜悦，气愤等情绪。例如：
A. What an interesting film!
B. How beautiful it is!
2. 根据语法结构的不同，将句子分为简单句，并列句，复合句以及并列复合句。
(1) 如果一个句子只有一个主谓结构，这个句子是简单句。例如：
A. She has finished her homework.
B. Both my brother and sister are teachers.
(2)如果一个句子包含两个或两个以上的互不依从的主谓结构，这个句子是并列句。并列句中的两个或两个以上的主谓结构通常由逗号和并列连词来连接。例如：
A. Honey is sweet, but the bee stings.
B. Type O is the most common blood type in the world, and type AB is the rarest.
(3)如果一个句子包含两个或两个以上的主谓结构，其中一个或一个以上的主谓结构充当另一个主谓结构中的某一(些)成分，如主语，宾语，定语等，该句为复合句。例如：
A. Because the luxury liner was traveling so fast,it was impossible to avoid the ghostly looking iceberg.
C. Some people say that it may result in some social problems in the future.
(4)当一个并列句中的一个(或更多的)主谓结构中包含有一个(或更多的)主谓结构时，这种句子为并列复合句。例如：
A. He was watching me or something for an hour or two, drawing back the curtain so little lest I catch him, but I saw his face, and I think I can see the anxiety upon it, the worried impatience.
B. I have brought what you need, but you haven't brought what I need.
3. 根据不同的修辞功能，句子可分为松散句，圆周句，对偶句，平行结构句，长句和短句。
(1) 松散句和圆周句。
在一个句子中，先介绍主要的信息，再介绍次要的信息，这样的句子叫松散句。松散句的结构比较松散，其各个部分往往能独立表示某一意义。在一个句子中先介绍次要的信息，再介绍重要的信息，即要到句子的末尾，句子的意思才完全表达清楚，这样的句子叫圆周句。圆周句的结构紧凑，只有读完整个句子，全句的整体意思才能显现出来。例如：
A. The workers here are mostly diligent, though not all.
B. The workers here are mostly, though not all，diligent.
C. He will go abroad if he has enough money.
D. If he has enough money, he will go abroad.
句A和句C为松散句，句B和句D为圆周句。
一般来讲，按正常语序排列的简单句、并列句，主句在前从句在后的复合句都属于松散句。松散句便于组织，便于理解，便于使用，是人们常用的句式。修饰语(尤其是状语)位于句首的简单句以及从句在前主句在后的复合句属于圆周句。圆周句的重心在后，可以造成一种悬念，抓住读者的注意力，因而可以收到一种特殊的效果。但圆周句不能使用太频繁，因为没有人愿意一直处于等待和悬念当中。
(2) 对偶句是在句中用平对或对称的结构来表现两种相反的意思。由于其结构匀称整齐，前后两层意思相反，可达到强调的效果。例如：
A. What is written without effect is in general read without pleasure.
B. Deeds show what we are; words what we should be.
(3) 平行结构句就是把两个或两个以上的结构相同，意义并重，语气一致的词、短语或句子排列成串形成一个整体，以加强语气，达到强调的目的。例如：
A. We can gain knowledge by reading, by reflection, by observation or by practice.
B. I have a dream that my four children will someday live in a nation where they will not be judged by the color of their skin but by the content of their character.
(4)长句和短句。
根据句子的长短，句子可分为长句和短句。例如：
A different form of reading might also be done, as it was in the past: reading aloud. Few pastimes bring a family closer together than gathering around and listening to mother or father to read a good story. The quite hour could become the story hour...
该段中前两句为长句，第三句为短句。一般来讲，短句短小精悍，可达到强调的目的，长句修饰成分多，可以清楚准确地表达复杂的思想。短句多运用于日常谈话，演讲，少儿作品或人物对话中；长句常用于政论文，科技文章以及文学作品的叙述描写等。
在写作时，应根据实际情况，交替使用各种句式。然而，值得注意的是，在变换句子开头和句式时，不能为变化而变化。在很大程度上，使用什么句式还跟文章的文体、内容等因素有关(例如在科技文体中多用长句和圆周句)，即内容决定形式。
