句子的一致性：指句子结构完整，时态、语态，语气及句式的一致，举重个部分共同表达一个独立、完整的思想。句子各成分之间的关系应协调，连贯，自然平稳。
下面来看一下句子不统一的几种情况：
1）句子意思表达不完整
× The lecture was given in such an interesting way.√ The lecture was given in such an interesting way that everyone enjoyed it very much.
2）句子的主从关系模糊
× We are going to visit John, and he is our English friend.√ We are going to visit John who is our English friend.
3) 连接词使用不当
× The main reason he was absent was because he was ill.√ The main reason he was absent was that he was ill.
4) 主谓不一致
× Every teacher and student were invited to go to the party.√ Every teacher and student was invited to go to the party.
5) 中心不明白
× I was watching a film last night, I suddenly found Mary sitting in front of me.√ When I was watching a film last night, I suddenly found Mary sitting in front of me.
句子的连贯性：指句子连接贯通，衔接自然。句子不论长短都应环环紧扣，符合语法、逻辑。请注意以下要点：
1）平行结构：把两个获两个以上意思相近或相对的、地位相当的成分已同意与发行是泛指在一起。其中以下三条规则须加以注意。
a)使用相同的语法来表达具有相同功能的句子成分，可运用并列连词and, but或or等。 × If you want to learn a foreign language well, you’d better try to think in it and speak it as much as poible.√ If you want to learn a foreign language well, you’d better try to think in it and to speak it as much as poible.
b)正确使用相关连词，如both„and, not „ but, not only „ but also等。 × Wang Lan is not only clever but also she is helpful.√ Wang Lan is not only clever but also helpful.
c)一个句子或段落中的人称、时态、语态要始终保持一致。
× One reason I like to go to school on foot is the physical exercise I get from it.√ I like to go to school on foot I regard it as a kind of physical exercise.
2）代词一致：句中代词应在数、性、人称等方面保持一致，或者与它所照应的名词词组在这些方面保持一致。如：
We each are responsible for our own jobs. We are each responsible for his own jobs.
3）代词与先行词一致：写作时应弄清楚代词究竟指代哪个名词，否则意思不明确，造成模棱两可的感觉。如：
× The old woman told the little girl that she was wrong.√ The old woman told the little girl, “I am wrong.” √ The old woman told the little girl, “You are wrong.”
句子的简练：累赘是写作常见的弊病之一。写作时应力求言简意赅，短小精悍。也就是说，在能说“走，天竺！”的时候千万不要说“你挑着担我骑着马迎来日出送走晚霞地去西天也就是天竺现在叫印度的地方如来佛祖那里取经到东土大唐来。”（咦？为什么大家都在吐？）众人：
那个„„总之，能简洁就简洁便是了。下面来看几句例句。
繁琐 My little bother always disappears from view when it is time for dinner.简洁 My little bother always disappears when it is time for dinner.
繁琐 The point I am trying to make is that practice makes perfect.简洁 I believe that practice makes perfect.
繁琐 I am writing to call your attention to the fact that„ 简洁 I am writing to remind you that„
句子的强调：强调能更有效地进行思想交流。写作者为使读者能更深入地了解自己的观点，有必要运用强调的手段。这就好比平时我们做笔记的时候，用荧光笔划出重点，为的就是能一目了然。那么写作的时候，也不要忘记在必要的地方使用一下highlight，让那些没有颜色的亮绿亮黄，一下子达到读者心里去。
常见的强调手段有如下几种：
1）句尾强调（End Emphasis）英语句子中通常将需要强调的部分置于句子末尾。 弱：He has achieved succe, I believe.强：He has, I believe, achieved succe.
2）倒装语序（Inverted Order）运用点到正常语序的手法达到强调。 正常：I did not believe what she said for a moment.倒装：Not for a moment did I believe what she said. 3）重复（Repetition）有意重复主要信息也可达到强调的目的。
„that government of the people, by the people, and for the people, shall not perish from the earth.
试着改变一下每个句子的开头
许多学生在写作中倾向于用与人有关系的词性，用名词和代词作为句子的开头，如 People，We，I，He，They，She等。但这种开头见多了，难免让人厌倦。试比较：
A.People throughout the country have greatly demanded all kinds of nutritious food.
B.There is a great demand acro the country for all kinds of nutritious food. 第一句改用非人称名词作为主语开头，第二句则用there ＋be句型开头。这样既改变了主语＋谓语＋宾语单调句型，又把想强调的意思突出出来。实际上，为了把文章写得生动活泼，除了用主语开头外，还可以用句子的其他成分开头。
1.以形容词或形容词组开头 如：
①Mary was very pleased and telephoned her mother． →Pleased，Mary telephoned her mother．
②The girl，hungry and thirsty，went back home． →Hungry and thirsty，the girl went back home．
2.以副词开头 如：The child stayed there quietly． →Quietly，the child stayed there．
3.以不定式开头 如：He got up very early to catch the bus． →To catch the bus，he got up very early．
4.以现在分词或过去分词开头 如：
①I was filled with anticipation when I came home from school that dark winter\'s day so long ago．
→Coming home from school that dark winter\'s day so long ago，I was filled with anticipation． ②If you give me enough time，I can do it well．
→Given enough time，I can do it well．
5.以介词短语开头 如：
Chester like many other adventurers had experienced fear and conquered it． →Like many other adventurers，Chester had experienced fear and conquered it．
6.以同位语开头 如：Sue，our monitor，always likes giving suggestions to everybody． →Our monitor，Sue，always likes giving suggestions to everybody．
7.以从句开头 如：
①Francis had already surprised his friends several times before he sailed round the world single-handed． →Before he sailed round the world single-handed，Francis had already surprised his friends several times．
②You will greatly improve your finished product if you have a quality control inspection． →If you have a quality control inspection， you will greatly improve your finished product．
有的学生在作文中使用过多简单句，成了简单句堆砌；有的写复杂句时，动辄用so， and，then，but，or，however，yet等非但达不到丰富表达方式的目的，反而使句子结构松散、呆板。为了避免这种现象，可以通过使用连接词，尤其是一些表示从属关系的连接词，如 who，which，that，because，since，although，after，as，before，when，whenever，if，unle，as if等，不仅能够丰富句型，而且还能够把思想表达得更清楚，意义更连贯。例如： Natural resources are very limited.They will be exhausted in the near future.It is not true.But it becomes a major concern around the world.This is a widely accepted fact.
这段文字用简单句表达，它们之间内在的逻辑关系含糊不清，意思支离破碎。如果使用连接词，将单句与其前后合并，形成主次关系，就把一个比较复杂的内容和关系表达得层次清楚、结构严谨。
例如：
It is a widely accepted fact that there is a major concern around the world for the exhaustion of limited natural resources in the near future，though it is unlikely to be true.
再如：
The Miiippi River is one of the longest rivers in the world，and in spring time it often overflows its banks，and the lives of many people are endangered.
此句用and把三个分句一贯到底，既乏味又可笑。如果使用了关系代词which，语义就会更连贯，语言也会更流畅：
The Miiippi River，which is one of the longest rivers in the world，often overflows its banks in the spring time，endangering the lives of many people.
