Before writing any essay or
even a paragraph, it is important to think, first about the topic and
then what you want to say about the topic. Most often, the topic is
easy, but the question then turns to what you want to say about the topic
which is the controlling idea. Topic sentences should always contain both (1)
and (2) a controlling idea.
Read the following topic sentences. They all
contain a topic (in red) and a controlling idea (in green). When your
introduction contains a clearly stated topic sentence such as one of the
following, your reader will know what to expect and, therefore, understand your
1. People can avoid
burglaries by taking certain
(The precautions for…)
2. There are several
advantages to growing up in a small town.
(The advantages of…)
3. Most US universities
require a 550 point TOEFL score
for a number of reasons.
(The reasons for…)
4. Air pollution in Mexico
City is the worst in the world for a number
(The causes of…) or (The effects of…)
5. Fixing a flat tire on a
bicycle is easy if you follow these steps.
(The steps for…)
6. There are several
enjoyable ways to travel between the US and
(The ways to…) or (The methods of…)
7. Animals in danger of
becoming extinct come from a wide range of
(The different countries… [parts, kinds, types])
8. Effective leadership
requires specific qualities that anyone can develop.
(The qualities (or characteristics or traits) of…)
9. Industrial waste poured
into Lake Michigan has led to dramatic
changes in its ability to support marine life.
(The effects of…)
10. In order to fully
explore the wreck of the Titanic, scientists must address
(The difficulties of…) or (The obstacles to…)
A carefully thought out topic sentence will serve
two important functions. First, it will provide you, the author, the means to
stay focused on your objective. It's a lot easier to write if you know what you
are going to write about! Second, a clearly stated topic sentence will provide
readers with the tools they need to clearly understand what you have to say.
These are important reasons to carefully consider topic sentences before