中心论点句，又叫做thesis statement，main point。它由至少两个部分构成：
l 写什么（Topic）：
即这篇文章是关原由网于谁、或关于什么东西、或什么事。
l 怎么了（Attitude，opinion，idea，point）：
即作者态度、观点，或要围绕主题论述的相关方面。
这两个部分，是一个主旨句的“核心”。在此基础上，我们再根据表达需要——如是否要突出某个信息点、是否要使用修辞技巧（比如让步或对比）——考虑添加相关必要信息，或者使用不同句式。
大体上，可以分这么三步走。
一、最直白、简约的写法。难度指数：★
一、最直白、简约的写法。难度指数：★
使用简单句，有主谓即可，是最直接、最简洁的表达。即什么事（人）、怎么了。
1. Owning a pet has many benefits.
写什么——owning a pet
怎么了——has many benefits
2. Living in the city has certain advantages over living in the suburbs.
写什么——Living in the city
怎么了——has certain advantages over living in the suburbs
相信绝大部分童鞋是可以做到这点的。
二、增加语块以丰富信息。难度指数：★★
在简单句基础上，增加定语或状语语块，如介词短语、不定式或分词词组，让句子意思更精准、更聚焦。
3. Before leaving home, every young person should have mastered certain key skills.
写什么——every young person
怎么了——should have mastered certain key skills before leaving home
此例中，Before leaving home也是“述语”的一部分，但是提前到句首了。
4. Walking will be banned on escalators as part of a trail designed to reduce congestion(拥堵)at some of the country’s busiest stations.
写什么——Walking
怎么了——will be bannedon escalators
如果仅仅说Walking will be banned on escalators，读者会不明就里，所以句子接下来增加了第一个介词语块as part of a trail（作为某种途径的一部分），第二个分词语块designed to reduce congestion（设计用来减少拥堵的），第三个介词语块at some of the country’s busiest stations（在有些最繁忙的车站）。
增加语块，丰富句子信息，这是大部分同学可以努力的方向。
三、活用句式以突出信息。难度指数：★★★
有时候为了突出句子中的重点信息，我们会使用学过的某些句式。注意：如果不是为了这个目的，而仅仅是为了“炫技”而“套用”，是不可取的。
5. The 20th century produced原由网three inventions that dramatically changed the world.
写什么——three inventions
怎么了——dramatically changed the world
这个句子，其实也可以用简单句，用后置介词短语来做定语: Three inventionsin the 20th centurydramatically changed the world.但为了突出The 20th century这个信息“二十世纪有三大发明改变了世界”，用了一个“主+谓+宾+定语从句”的方式。
类似这样为了突出某个信息块的主旨句式，还有It形式主语句、There be句式。例如：
There isa clear relationship between fatness and indoor play.（突出clear relationship）
There aregood reasons whysome people feel the need to make significant changes to their lives from time to time.（突出good reasons）
Ithas been announced thata comet is heading towards the Earth. （突出消息可靠性）
6. Youth sport has the potential to accomplish three important objectives in children’s development.
写什么——Youth sport
怎么了——toaccomplish three important objectivesin children’s development
这句话可以用简单的表达法，即Youth sport can possiblyaccomplish three important objectives in children’s development，但是用has the potential to代替了can possibly，即“有……的可能性”。
做到这点，语法基础扎实是前提，知道一个句式怎么用、为什么用更重要。
四、常见的三种花样开头。难度指数：★★★★
有时候，主题句可以不那么“直接”。但前提是：增加的信息一定是有用的。常见的几种句子如：让步式、举例式、条件式。
7. Pizza may be great, but too much of it is certainly not healthy.
写什么——too much of it（pizza）
怎么了——is certainly not healthy
“让步式”开头的主题句，大多用while，though，despite，however，but，yet这类标记词。
8. If you love various cheeses, sauces, and pastas, UUhXVBYTyou would love the meals you eat in Italy.
写什么——meals ... in Italy
怎么了——you would love(the meals you eat in Italy)
“条件式”开头的主题句，主要的信息在后半句。
9. Obesity is on the rise in America and the leading cause of numerous medical problems. The leading causes of obesity are overeating and lack of physical activity.
写什么——The leading causes of obesity
怎么了——are overeating and lack of physical activity
“例子（或现象）式”开头，是为了引出真正的主题句。
最后，我们通过几个坏的例子，看看写主题句会有哪些“坑”。
Nick learns hard lessons from his experiences.
过于模糊笼统——什么经历？什么教训？这属于什么也没说的主题句。
Nick finds expensive items in his sister's shed that were purchased with fraudulent（欺骗性的）credit cards.
过于具体琐碎——此事与文章有何关系？这属于缺乏概括性的主题句。
One of the strongest arguments in favour of limiting the amount of time that youngsters spend in front of screens is that children need to be more active in order t原由网o have a healthy lifestyle.
过于炫耀句法——需要把话说的这么复杂么？这属于华而不实的主题句。
我们看看修改后的句子：
第一个句子修改后：
Nick struggles to overcome his trust issues because his friends and family aren't always trustworthy.
第二个句子修改后：
The amount of time that youngsters spend in front of screens should be limited because children need to be more active in order to have a healthy lifestyle.
【考考你】按照上面的原则，看看下面两个句子有什么不合适，修改一下。
1. The first reason why letting children care for animals is not the best way to teach them about responsibility is that it could negatively impact a child’s health.
2. First and foremost, television, invented in the last century, with its 原由网wide availability and increasingly prosperous programs, becomes one of the most powerful means of communication in history, and is more and more difficult to ignore.
