Part Three: Write an opinion paragraph (5 sentences) that expresses whether you agree, disagree, or are sitting on the fence (in the middle) for the topic. When you write your paragraph, start with a topic sentence similar to this: "I believe that stem cells should (not) be used in scientific research." The next three sentences should support your topic sentence. The last sentence will be your concluding sentence, which restates your opinion. For example, as you can see, stem cell research is a valuable part of scientific research.