Topic sentence in a paragraph A paragraph must include a topic sentence. It is a complete sentence

It provides:  a key to the paragraph;  the main idea.

It has:  a topic;  a controlling idea.

Definition  A topic sentence provides a key to what the paragraph is all about. It provides the main idea of the paragraph. It consists of the topic ~ what the paragraph is about, and the controlling idea ~ how the writer will write about the topic. For example,

Examples  Topic: young drivers in car accidents  Controlling Idea: 2 main reasons why they are involved more than older drivers The topic sentence can now be written like the following: The topic sentence can now be written like the following:  There are two main factors that cause younger drivers to be involved in more car accidents than older drivers

Examples  Topic: young drivers in car accidents  Controlling Idea: 2 main reasons why they are involved more than older drivers The topic sentence can now be written like the following: The topic sentence can now be written like the following:  There are two main factors that cause younger drivers to be involved in more car accidents than older drivers

More Examples about topic sentences TOPIC TOPIC 1. Convenience foods 2. American cooking 3. The average American teenager CONTROLLING IDEA CONTROLLING IDEA  are easy to prepare  reflects the native foods of America’s immigrant population  consumes enormous quantities of junk food.

Explanation  In the first example, the topic is named: convenience food. A specific comment is then made about the topic: they are easy to prepare. From this sentence, the reader immediately knows that the supporting sentences in the remainder of the paragraph will explain or prove how quick and easy it is to prepare convenience foods and perhaps give some examples (frozen dinners, canned soups, etc.).

How about the second?  What do the readers expect to read in the paragraph?

How about the third paragraph?  What will the writer discuss in the paragraph?