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Module 1: Grammar Module 2: Sources Module 3: Structure
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Unit 1: Planning your essayUnit 2: Structuring paragraphsUnit 3: Introductions & conclusionsUnit 4: Writing persuasivelyUnit 5: Writing cohesively

Topic sentences

This section explains the specific purpose of the topic sentence in a paragraph. It provides you with examples of topic sentences and the opportunity to analyse their usage.

What do topic sentences do?

Topic sentences have three crucial roles in paragraph writing.

  1. The topic sentence introduces a controlling idea. This idea will determine the content of the paragraph – what goes in and what is left out. You should always be able to demonstrate how every item of information in your paragraph relates to the controlling idea expressed in the topic sentence.
    A controlling idea may take the form of:
    • a new argument;
    • a new aspect of an existing argument.
  2. The topic sentence links the controlling idea clearly to a preceding idea in the text. This idea may be the thesis statement in the introduction, a previous argument or a previous point in the same argument.
    Topic sentences may make these links by:
    • repeating key words (or synonyms for them) from the thesis statement in your introduction or the main assertion in your individual arguments.
    • using linking words or phrases such as another aspect of, a second feature of, in addition to this …
  3. The topic sentence orients the reader to the content in the paragraph. It sets up the expectation that:
    • all the information in the paragraph will be demonstrably related to the controlling idea.
    • only information demonstrably related to the controlling idea will be included in the paragraph.