A topic sentence is the most important sentence in a paragraph. Sometimes referred to as a focus sentence, the topic sentence helps organize the paragraph by summarizing the information in the paragraph. In formal writing, the topic sentence is usually the first sentence in a paragraph (although it doesn't always have to be). A topic sentence essentially tells what the rest of the paragraph is about. All sentences after it have to give more information about the sentence, prove it by offering facts about it, or describe it. For example, if the topic sentence concerns the types of endangered species that live in the ocean, then every sentence after that needs to expound on that subject. Topic sentences also need to relate back to the thesis of the essay. The thesis statement is like a road map that will tell the reader or listener where you are going with this information or how you are treating it.
The thesis statement is that sentence or two in your text that contains the focus of your essay and tells your reader what the essay is going to be about. Although it is certainly possible to write a good essay without a thesis statement (many narrative essays, for example, contain only an implied thesis statement), the lack of a thesis statement may well be a symptom of an essay beset by a lack of focus. Many writers think of a thesis statement as an umbrella: everything that you carry along in your essay has to fit under this umbrella, and if you try to take on packages that don't fit, you will either have to get a bigger umbrella or something's going to get wet.The thesis statement is also a good test for the scope of your intent. The principle to remember is that when you try to do too much, you end up doing less or nothing at all. Can we write a good paper about problems in higher education in the United States? At best, such a paper would be vague and scattered in its approach. Can...