Basic Paragraph Structure

In many languages, the fundamental unit of composition is the paragraph.  A paragraph consists of several sentences that are grouped together.  This group of sentences together discuss one main subject.   In U.S. formal academic English, paragraphs have three principal parts.  These three parts are the topic sentence, body sentences, and the concluding sentence.  We will also talk briefly about details in paragraphs.

The Topic Sentence

A topic sentence usually comes at the beginning of a paragraph; that is, it is usually the first sentence in a formal academic paragraph.  (Sometimes this is not true, but as you practice writing with this online lesson site, please keep to this rule unless you are instructed otherwise.)  Not only is a topic sentence the first sentence of a paragraph, but, more importantly, it is the most general sentence in a paragraph.  What does "most general" mean?  It means that there are not many details in the sentence, but that the sentence introduces an overall idea that you want to discuss later in the paragraph.

For example, suppose that you want to write a paragraph about the natural landmarks of your hometown.   The first part of your paragraph might look like this:

       My hometown is famous for several amazing natural features.  First, it is noted for the Wheaton River, which is very wide and beautiful. Also, on the other side of the town is Wheaton Hill, which is unusual because it is very steep.

(Notice how the first sentence begins with "My hometown..." a few spaces to the right of the paragraph edge.  This is an indentation.  All paragraphs in English MUST begin with an indentation.)

Note how the first sentence, My hometown, Wheaton, is famous for several amazing geographical features, is the most general statement. This sentence is different from the two sentences that follow it, since the second and third sentences mention specific details about the town's geography, and are not general statements.

Here are some examples of sentences that cannot be used as topic sentences. Can you figure out why they are inappropriate? 

     1.      My hometown is famous because it is located by Wheaton River, which is very wide, and because it is built near an unusually steep hill called Wheaton Hill.

     2.      There are two reasons why some people like to buy cars with automatic transmission and two reasons why others like cars with manual transmission.

     3.      Clouds are white.

The problem with sentence #1 is that it contains too many details. Topic sentences are general, and details should appear later in the paragraph. A better topic sentence would be like the one mentioned above, My hometown is famous for several amazing geographical features.

Sentence #2 is not appropriate as a topic sentence because it mentions two topics, not just one. Paragraphs are usually about one main thing and so their topic sentences should also be about only one main thing.

The problem with sentence #3 is that it is too general. It is also very boring! Would you like to read a paragraph with this topic sentence? Most people would not.

We can rewrite sentences #2 and #3 in the following ways to make it better:

There are two reasons why some people like to buy cars with automatic transmission.

 OR (in a different paragraph):

·         There are two reasons why some people like cars with manual transmission.

·         The shapes of clouds are determined by various factors.