A paragraph has three major structural parts: a topic sentence, supporting sentences, and a concluding sentence.
The topic sentence states the main idea of the paragraph. It not only names the topic of the paragraph, but it also limits the topic to one or two areas that can be discussed completely in the space of a single paragraph. The specific area is called the controlling idea. Notice how the topic sentence of the model states both the topic and the controlling idea:
TOPIC CONTROLLING IDEA
Gold, a precious meal, is prized for two important characteristics.
Supporting sentences develop the topic sentence. That is, they explain the topic sentence by giving reasons, examples, facts, statistics, and quotations. Some of the supporting sentences that explain the topic sentence about gold are:
First of all, gold has a lustrous beauty that is resistant to corrosion.
For example, a Macedonian coin remains as untarnished today as the day it was minted twenty-three centuries ago.
Another important characteristic of gold is its usefulness to industry and science.
The most recent use of gold is in astronauts' suits.
The concluding sentence signals the end of the paragraph and leaves the reader with important points to remember:
In conclusion, gold is treasured not only for to beauty but also for the utility.
In addition to the three structural parts of a paragraph, a good paragraph also has the elements of unity and coherence.
Unity means that you discuss only one main idea in a paragraph. The main idea is stated in the topic sentence, and then each and every supporting sentence develops that idea. If, for example, you announce in your topic sentence that you are going to discuss two important characteristics of gold, discuss only those. Do not discuss any other ideas, such as the price of gold or gold mining.
Coherence means that your paragraph is easy to read and understand because (1) your supporting sentences are in some kind of logical order and (2) your ideas are connected by the use of appropriate transition signals. For example, in the paragraph about gold, there are two supporting ideas: Gold is beautiful, and gold is useful. Each of these supporting ideas is discussed, one after the other, and an example is given for each one. This is one kind of logical order. Furthermore, the relationship between the ideas is clearly shown by using appropriate transition words and phrases such as first of all, for example, another important characteristic, and in conclusion.
In summary, a well-written paragraph contains five elements: a topic sentence, supporting sentences, a concluding sentence, unity, and coherence.
The first line of a paragraph is indented. This is easy to do. Just move the first line in about a half inch. This gap or open space in the first line is called an indentation.