WHAT IS A PARAGRAPH?
Paragraphs are the building blocks of papers. A paragraph is a group of sentences that develops one main idea. A paragraph may stand by itself as a complete piece of writing, or it may be a section of a longer piece of writing, such as an essay.
No single rule can prescribe how long a paragraph should be the unity and coherence of ideas among sentences is what constitutes a paragraph, but a paragraph that is too short can make a reader think that some basic information is missing. On the other hand, a paragraph that is too long will likely make a reader lose interest. An effective paragraph must be long enough to develop the main idea the writer is expressing, usually six or seven sentences in length, but no more than ten or twelve sentences. While it is true that newspapers or magazines take liberties with the paragraph form and often have paragraphs as short as a single sentence, a well-developed piece of writing will seldom present a single sentence as a paragraph (unless the sentence is a piece of dialogue).
Basic paragraph structure
A paragraph consists of several sentences that are grouped together. This group of sentences together discusses one main subject. Paragraphs have three basic principal parts. These three parts are the topic sentence, body sentences (supporting sentences), and the concluding sentence. A topic sentence is a sentence whose main idea or claim controls the rest of the paragraph. It consists of a topic and controlling idea, which is the point the writer makes about the title. The topic sentence is usually the first sentence of a paragraph, but not necessarily. It may come, for example, after a transition sentence; it may even come at the end of a paragraph.
Topic sentences are not the only way to organize a paragraph, and not all paragraphs need a topic sentence. For example, paragraphs that describe, narrate, or detail the steps in an experiment do not usually need topic sentences. Topic