I. THE THREE PARTS OF A PARAGRAPH
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.

II. UNITY AND COHERENCE
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.
III. INDENTATION
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.