The topic sentence states the central point of the paragraph. This will be in the form of one of the reasons in support of the thesis statement made in the introduction. Explain: These sentences will build on the topic sentence by illustrating the point further, often by making it more specific. This activity was created to help students write topic sentences for the three body paragraphs of their five-paragraph persuasive essay. In formal writing, the topic sentence is usually the first sentence in a paragraph (although it doesn't have to be).