Reading and Finding The Main Idea Help (page 3)
Introduction to Finding the Main Idea
Just as there's a motive behind every crime, there's also a motive behind every piece of writing.
All writing is communication. A writer writes to convey his or her thoughts to an audience, the reader: you. Just as you have something to say (a motive) when you pick up the phone to call someone, writers have something to say (a motive) when they pick up a pen or pencil to write. Where a detective might ask, "Why did the butler do it?" the reader might ask, "Why did the author write this? What idea is he or she trying to convey?" What you're really asking is, "What is the writer's main idea?"
Finding the main idea is much like finding the motive of the crime. It's the motive of the crime (the why) that usually determines the other factors (the who, what, when, where, and how). Similarly, in writing, the main idea also determines the who, what, when, and where the writer will write about, as well as how he or she will write.
Subject vs. Main Idea
There's a difference between the subject of a piece of writing and its main idea. To see the difference, look again at the passage about the postal system. Don't skip over it! You read it in Lesson 1, but please read it again, and read it carefully.
Today's postal service is more efficient and reliable than ever before. Mail that used to take months to move by horse and foot now moves around the country in days or hours by truck, train, and plane. First-class mail usually moves from New York City to Los Angeles in three days or less. If your letter or package is urgent, the U.S. Postal Service offers Priority Mail and Express Mail services. Priority Mail is guaranteed to go anywhere in the United States in two to three days or less. Express Mail will get your package there overnight.
You might be asked on a standardized test, "What is the main idea of this passage?"
For this passage, you might be tempted to answer, "the post office."
But you'd be wrong.
This passage is about the post office, yes—but "the post office" is not the main idea of the passage. "The post office" is merely the subject of the passage (who or what the passage is about). The main idea must say something about this subject. The main idea of a text is usually an assertion about the subject. An assertion is a statement that requires evidence ("proof") to be accepted as true.
The main idea of a passage is an assertion about its subject, but it is something more: It is the idea that also holds together or controls the passage. The other sentences and ideas in the passage will all relate to that main idea and serve as "evidence" that the assertion is true. You might think of the main idea as a net that is cast over the other sentences. The main idea must be general enough to hold all of these ideas together.
Thus, the main idea of a passage is
- an assertion about the subject.
- the general idea that controls or holds together the paragraph or passage.
Look at the postal service paragraph once more. You know what the subject is: "the post office." Now, see if you can determine the main idea. Read the passage again and look for the idea that makes an assertion about the postal service and holds together or controls the whole paragraph. Then answer the following question:
Which of the following sentences best summarizes the main idea of the passage?
- Express Mail is a good way to send urgent mail.
- Mail service today is more effective and dependable than it was in the past.
- First-class mail usually takes three days or less.
Because choice a is specific—it tells us only about Express Mail—it cannot be the main idea. It does not encompass the rest of the sentences in the paragraph—it doesn't cover Priority Mail or first-class mail. Choice c is also very specific. It tells us only about first class mail, so it, too, cannot be the main idea.
But choice b—"Mail service today is more effective and dependable than it was in the past"—is general enough to encompass the whole passage. And the rest of the sentences support the idea that this sentence asserts: Each sentence offers "proof" that the postal service today is indeed more efficient and reliable. Thus, the writer aims to tell us about the efficiency and reliability of today's postal service.
TIP: If you are having trouble identifying the main ideas in a story, try asking yourself these questions:
What unifying concept is the author striving to communicate?
Is there a moral or lesson that the author is trying to teach?
Are there any reoccurring symbols or imagery that the author is using to communicate a deeper meaning?
You'll notice that in the paragraph about the postal service, the main idea is expressed clearly in the first sentence: "Today's postal service is more efficient and reliable than ever before." A sentence, such as this one, that clearly expresses the main idea of a paragraph or passage is often called a topic sentence.
In many cases, as in the postal service paragraph, the topic sentence is at the beginning of the paragraph. You will also frequently find it at the end. Less often, but on occasion, the topic sentence may be in the middle of the passage. Whatever the case, the topic sentence—like "Today's postal service is more efficient and reliable than ever before"—is an assertion, and it needs "proof." The proof is found in the facts and ideas that make up the rest of the passage. (Not all passages provide such a clear topic sentence that states the main idea. Less obvious passages will come up in later lessons.)
Identifying Topic Sentences Practice and Answers
Remember that a topic sentence is a clear statement of the main idea of a passage; it must be general enough to encompass all the ideas in that passage, and it usually makes an assertion about the subject of that passage. Knowing all that, you can answer the following question even without reading a passage.
Which of the following sentences is general enough to be a topic sentence?
- The new health club has a great kickboxing class.
- Many different classes are offered by the health club.
- Pilates is a popular class at the health club.
- The yoga class is offered on Saturday mornings.
The answer is choice b, "Many different classes are offered by the health club." Choices a, c, and d are all specific examples of what is said in choice b, so they are not general enough to be topic sentences.
Now look at the following paragraph. Underline the sentence that expresses the main idea, and notice how the other sentences work to support that main idea.
Erik always played cops and robbers when he was a boy; now, he's a police officer. Suzanne always played school as a little girl; today, she is a high-school math teacher. Kara always played store; today, she owns a chain of retail clothing shops. Long before they are faced with the question, "What do you want to be when you grow up?" some lucky people know exactly what they want to do with their lives.
Which sentence did you underline? You should have underlined the last sentence: "Long before they are faced with the question 'What do you want to be when you grow up?' some lucky people know exactly what they want to do with their lives." This sentence is a good topic sentence; it expresses the idea that holds together the whole paragraph. The first three sentences—about Erik, Suzanne, and Kara—are specific examples of these lucky people. Notice that the topic sentence is found at the end of the paragraph.
Among the following eight sentences are two topic sentences. The other sentences are supporting sentences. Circle the two topic sentences. Then write the numbers of the supporting sentences that go with each topic sentence.
- Finally, there is a concierge on duty 24 hours a day.
- Some duties, like writing reports, have no risk at all.
- For example, there is a pool on the top floor.
- Not all police duties are dangerous.
- Others, like traffic duty, put police officers at very little risk.
- Tenants of the luxury apartment building enjoy many amenities.
- Still other duties, like investigating accidents, leave officers free of danger.
- In addition, the lobby has a dry cleaner, an ATM, and a coffee shop.
Sentences 4 and 6 are the two topic sentences because both make an assertion about a general subject. The supporting sentences for topic sentence 4, "Not all police duties are dangerous," are sentences 2, 5, and 7. The supporting sentences for topic sentence 6, "Tenants of the luxury apartment building enjoy many amenities," are the remaining sentences 1, 3, and 8.
Here's how they look as paragraphs:
Not all police duties are dangerous. Some duties, like writing reports, have no risk at all. Others, like traffic duty, put police officers at very little risk. Still other duties, like investigating accidents, leave officers free of danger.
Tenants of the luxury apartment building enjoy many amenities. For example, there is a pool on the top floor. In addition, the lobby has a dry cleaner, an ATM, and a coffee shop. Finally, there is a concierge on duty 24 hours a day.
You might have noticed that the supporting sentences in the first paragraph about police duties begin with the following words: some, others, and still other. These words are often used to introduce examples. The second paragraph uses different words, but they have the same function: for example, in addition, and finally. If a sentence begins with such a word or phrase, that is a good indication it is not a topic sentence—because it is providing a specific example.
Here are some words and phrases often used to introduce specific examples:
- for example
- for instance
- in addition
- in particular
If you're having trouble finding the main idea of a paragraph, you might try eliminating the sentences that you know contain supporting evidence.
Now you can answer the last question—the why. What is the writer's motive? What's the main idea he or she wants to convey? By finding the sentence that makes an assertion about the subject of the paragraph and that encompasses the other sentences in the paragraph, you can uncover the author's motive.
TIP: To identify the main idea in a story it can be helpful to create a story map or graphic organizer. In separate boxes in your graphic organizer, you should include
- the names of major and minor characters.
- major and minor settings.
- conflicts occurring between characters.
- key events.
- major resolutions.
- author's purpose. (Is the author's goal to entertain, teach, inform, or persuade readers to embrace a particular philosophical viewpoint or concept?)
More practice exercises for this concept can be found at Reading Comprehension Strategies Practice Test.
Test your knowledge at Reading Comprehension Final Practice Test.
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