The topic sentence

In our previous entry, we explained the structure of a paragraph and how to write a good one. The key idea was that a paragraph is composed of three main elements: topic sentence, supporting sentences, and concluding sentence. In this entry, we will explain in detail what a topic sentence is and the relevance it has in a paragraph. A topic sentence has some characteristics and clear functions we will explain as follows. 

It is usually the first sentence of a paragraph, which states its main idea.

The topic sentence must state only one idea clearly because it guides the reader to understand what the paragraph is going to talk about. This topic sentence at the beginning of the paragraph creates expectations, i.e., the reader makes predictions about what is coming next based on the idea stated. For example, if my topic sentence is “Dogs are the best pets in the world”, the reader expects to read about the reasons why the writer of the paragraph says so.

A good topic sentence is not a general fact that everyone accepts as true. 

For example, a bad topic sentence would be “The sun rises every morning”. The information in this sentence is true, but it is a general fact and is not a good choice for a topic sentence. What else can we say about that? nothing very interesting.

A topic sentence is specific.

For example, if we write “Academic writing is important”, our readers will not know what to expect. The information in that sentence is too general and does not help create expectations. A better version of that sentence could be something like “Improving your academic writing is crucial for you to succeed at college”. This topic sentence lets us know immediately what is coming next. We will probably read about arguments related to the relevance of academic writing for college students and their academic performance.

Even though a topic sentence must be specific, it cannot be too specific.

For example, if our topic sentence is “Whales are warm-blooded and have a layer of fat or blubber under the skin”, how can the writer develop this main idea? what else can the writer say about it? probably not much because that is a very specific characteristic of the main topic of the paragraph (whales). 

These four ideas are key to write a good topic sentence for your paragraph. Keep them in mind because your topic sentence is the one that creates expectations and lets your reader know what your paragraph talks about. 

*Adapted from Folse, K. (2010). Great writing 2: Great Paragraphs.

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