无论雅思托福的议论文写作，都需要对论点进行充分详细的论述，下面的文章，我们就来看一看雅思写作议论文段落的3中展开方法。

在应试型(雅思或新托福等)议论文写作中，通常遵循introduction-body-conclusion(引言段-主体段-结论段)的“三步曲”。Body(主体)段落提供了论证观点的理由，是整个文章的主体，在评分中占有很大的比重。例如一篇满分的雅思作文(9分)必须“presentsa fully developed position in answer to the question with relevant, fullyextended and well supported ideas”。这里的“fully extended / wellsupported”，必须通过主体段来体现。新托福的满分作文(5分)也要求“is well organized and well developed,using clearly appropriate explanations, exemplifications, and/ordetails”，同样必须通过主体段落发展来实现。

一般来说，一篇议论文必须包含至少两个主体段。每个主体段都必须有明确的主题句“topic sentence”和若干支持句“supportingsentences”。他们共同组成文章的理由段，对全文的论点提供理由支持。建议初学者在练习议论文写作时，必须遵循理由段发展的几个简单原则，这对迅速完成理由段、构建连贯和理由充分的议论文大有帮助。这几个简单原则包括：

1. Write a topic sentence for each paragraph you plan to write. Each topicsentence should relate to your thesis statement and introduce what the paragraphwill be about. If you find that the topics you want to discuss do not supportthe thesis statement you have written, revise your thesis statement orreconsider your topic sentences.(每个主体段都必须有一个明确的主题句)

2. Write ideas that support your topic sentences. The topic sentence foreach paragraph tells the reader what the paragraph will be about. The ideasstated in the rest of the paragraph should all relate to the topicsentence.(支持句必须围绕主题句展开)

根据第2条的原则，我们来看看下面这个主体段：

Hobbies are important for many reasons. First, a hobby can be educational.For example, if the hobby is stamp collecting, the person can learn about thecountries of the world and even some of their history. Second, engaging in ahobby can lead to meeting other people with the same interests. A person canalso meet other people by going to the school. Third, a person's free time isbeing used in a positive way. The person has no time to be bored or get intomischief while engaged in the hobby. Finally, some hobbies can lead to a futurejob. A person who enjoys a hobby-related job is more satisfied with life.

这段话的topic sentence很明显-“Hobbies are important for manyreasons”，之后的支持句从三方面阐述hobby的重要性(first, second, third)，但段中这句话"A person can alsomeet other people by going theschool"与hobby重要的原因没有关系，因此削弱了整个段落的连贯性与统一性，应该被去掉。

3. Add details. To write a more fully developed paragraph, you need to adddetails to your supporting ideas. Your details can be facts, examples, personalexperiences, or descriptions.(需要用多种方式提供细节展开段落)

根据第3条的原则，我们来看下面这个段落：

The Smithsonian Institution is worth visiting for a number of reasons. TheSmithsonian Institution comprises various museums that offer something foreveryone. These museums include the National Museum of History and Technology,the National Aeronautics and Space Museum, the National Collection of Fine Arts,the National Museum of Natural History, and several others. A person can do morethan just look at the exhibits. For example, in the insect zoo at the NationalMuseum of Natural History, anyone who so desires can handle some of theexhibits. The museums provide unforgettable experiences. In climbing through theSkylab exhibit at the National Aeronautics and Space Museum, I was able toimagine what it would be like to be an astronaut in space. Movies shown atregular intervals aid in building an appreciation of our world. In the NationalAeronautics and Space Museum, there is a theater that has a large screen. Whenthe movie is shown, it gives the viewer the feeling that he or she is in themovie itself, either floating above the Earth in a hot-air balloon or hanggliding over cliffs.

这是一个成功的主题段，请注意这段话段落细节展开的几种形式-提供事实、举例、个人经历和描述。我们把这个段落拆分后进行分析：

Topic sentence

(主题句)The Smithsonian Institution is worth visiting for a number ofreasons.

Supporting idea 1

(支持理由1)The Smithsonian Institution comprises various museums that offersomething for everyone.

Details – facts

(细节展开-提供事实)These museums include the National Museum of History andTechnology, the National Aeronautics and Space Museum, the National Collectionof Fine Arts, the National Museum of Natural History, and several others.

Supporting idea 2

(支持理由2)A person can do more than just look at the exhibits.

Details – examples

(细节展开-举例)For example, in the insect zoo at the National Museum of NaturalHistory, anyone who so desires can handle some of the exhibits.

Supporting idea 3

(支持理由3)The museums provide unforgettable experiences.

Details – personal

experience

(细节展开-个人经历)

In climbing through the Skylab exhibit at the National Aeronautics andSpace Museum, I was able to imagine what it would be like to be an astronaut inspace.

Supporting idea 4

(支持理由4)Movies shown at regular intervals aid in building an appreciation ofour world.

Details – description

(细节展开-描述)In the National Aeronautics and Space Museum, there is a theaterthat has a large screen. When the movie is shown, it gives the viewer thefeeling that he or she is in the movie itself, either floating above the Earthin a hot-air balloon or hang gliding over cliffs.