Topic Sentences
The topic sentence of a paragraph or passage is frequently the very first sentence—frequently, but not always. So you cannot just assume that the first sentence in a paragraph is the topic sentence.
The topic sentence will lay out the general topic of a passage (which is why it's called the topic sentence), while other sentences will provide greater detail and proof of the topic sentence. Look again at the preceding passage about paints, and find the topic sentence in that paragraph.
Which of the following sentences is the topic sentence in the painting paragraph?
- "There are many different types of paint available today…"
- "Selecting the right paint to use for your hobby can be a difficult matter…"
- "When painting miniature lead soldiers, for example…"
- "You would need to choose between acrylic paints…"
- "Understanding the strengths and weaknesses of each type of paint will make your job much easier."
The first sentence, choice a, is introducing the topic of the passage, which is paint. Therefore, a is the correct choice. Notice that all the other sentences make statements of opinion—such as "selecting the right paint can be a difficult matter"—and therefore, they are too specific to be the topic. Such specific statements are the main idea, the point that the author is trying to prove, whereas the topic is whatever general thing the main idea is about—in this case, paint. The main idea is also often a general idea that needs details to support it. Both the main idea and the topic are general. The difference between the two is that while the topic is merely the subject of the passage, the main idea is the point that the author is making about that subject.
This leads us to the next type of sentence: the thesis statement.
Thesis Statements
A topic sentence introduces the general topic of a passage, while a thesis statement makes a point that must be proven. As we've already seen, the topic sentence of the passage about paint was the first sentence in the paragraph, which introduced the topic of paint.
But the thesis statement is the sentence in that paragraph which makes a claim that could be considered a matter of opinion, an idea that must be proven. In our paint passage, the thesis statement is actually the very last sentence: Understanding the strengths and weaknesses of each type of paint will make your job much easier.
A thesis is an idea, a proposition, a matter of opinion that can be debated. In the example under consideration, a person might conceivably argue that understanding the strengths and weaknesses of paint is actually not helpful to a hobbyist; it is a matter of opinion whether or not understanding paint will help you with any given project. This sentence, in other words, presents an opinion which is open to debate and requires support. This is what distinguishes a main idea (stated in the thesis statement) and a topic (introduced in the topic sentence).
As a general rule, the thesis statement is the main idea of a passage, so once you have identified the thesis statement, you've also identified the main idea.
Finding the Main Idea in Nonfiction
Most works of nonfiction that you will encounter are intended to persuade the reader of some point or opinion. Some writing may seem purely objective—news articles, for example—but in reality, even newspapers and magazines are presenting information that could be debated. This type of writing is therefore called persuasive writing.
Persuasive writing often follows a simple pattern, in which the author presents his or her opinion and then supports that opinion with details that prove the opinion to be true. Later in this chapter we will discuss these supporting details more, but for now it's important to know how to use supporting details to find a passage's main idea.
The following diagram will help to illustrate the pattern that you will notice in most nonfiction writing.
Most nonfiction passages that you'll encounter on the GED Language Arts, Reading exam will follow this basic pattern. The author will state a main idea, and then support that idea with evidence to prove that it's true. You must be on guard, however, because sometimes the main idea will be stated at the end or even in the middle of a paragraph—not necessarily at the very beginning. But as you learn to recognize supporting data, you will also gain the ability to quickly spot the main idea.
Read the following paragraph, underline supporting details, and circle the main idea.
Automobile airbags have been known to knock passengers unconscious, and can even threaten the life of a child when they deploy. Airbags expand at such a rapid pace, with such tremendous velocity, that they can actually hit a person in the face with more force than he would sustain if he merely hit the dashboard. The intended purpose of airbags is to cushion any impact which the passenger might sustain in a collision, but in reality they merely create a dramatic collision of their own. There is no doubt that airbags should be an option, not a requirement in modern cars.
Which sentence in that paragraph presents the main idea, and which are supporting details that prove the main idea correct? This paragraph is tricky because the main idea is actually not the first sentence—it's the last sentence. That's why it is important to pay attention to the whole passage and not let your attention trail off, because the last sentence is often just as important as the first. The author is presenting his opinion that airbags should be optional rather than mandatory in modern cars, but he opens the paragraph with supporting evidence that proves his opinion. So the main idea in this paragraph is found in the last sentence, while all other sentences provide supporting information.
Supporting data will usually be statements of fact, things that are accepted as true and not open to debate. Notice that the first sentence in the sample paragraph states that airbags have knocked people unconscious. This is a fact, not an opinion. The second sentence states that airbags expand so fast that they can create a severe impact to a person's face—again, another fact and not an opinion. The only opinion statement in the above paragraph is the final sentence, which suggests that airbags should be an option on cars. You know that this is an opinion because there will be readers who disagree.
Of course, facts themselves can be debated, such as the author's claim that the airbag's force is greater than hitting the dashboard. But your job on the GED is not to determine whether the facts are accurate; your job is merely to distinguish between the main idea of a passage and the supporting details. In other words, remember that the author is presenting what he or she considers to be facts in order to support a main idea, and you can use those supporting facts to help point out the passage's main idea.
Main Ideas versus Supporting Details
To determine quickly whether a sentence is a supporting detail or a main idea, just ask yourself this question: Does this sentence tell me specific information, such as facts and figures; or does this sentence make a statement that could easily be debated? If the sentence can easily be argued with, it's most likely the main idea. If the sentence provides facts and figures that are probably not open to much debate, then it's a supporting detail.
Let's look at another example. Again, underline supporting details (facts and figures) and circle the main idea (debatable opinion).
Walnut trees are not a good selection for landscaping around private homes. Walnuts secrete a chemical into the soil that can kill other plants nearby. In fact, this chemical is not only secreted into the soil, but also carried to surrounding areas in the leaves, twigs, and nuts that the tree drops. This chemical will cause many plants to die—plants that are commonly used around homes. Studies have shown, for example, that more than 50% of homes in America have trees and shrubs in their yards that are susceptible to the walnut's secretions.
All the sentences in this paragraph provide facts and figures, things which are commonly accepted and not open to debate—all the sentences, that is, except for the first. In the first sentence, the author presents an opinion by stating that walnut trees are not good for landscaping. That is clearly a matter of opinion, while the other sentences present details that are not matters of opinion—such as the fact that walnut trees secrete a chemical into the soil.
Words That Signal Supporting Details
Another good way to spot supporting data is to look for certain words and phrases that are frequently used to introduce evidence. Here are some of these words:
A quick way to find the topic sentence in a paragraph is to begin by eliminating sentences that begin with these words. Sentences beginning with these signal words will usually be supporting data, and not the main idea. Don't eliminate them without reading the whole sentence, though. Just use the signal words as clues to which sentences are probably playing supporting roles.
Finding the Main Idea in Fiction
The main idea in literature is sometimes also called the theme. Don't be misled by such terminology, however; finding the theme in literature is the same as finding the main idea in nonfiction.
Remember also that the theme (or main idea) is different from the subject. The subject is the thing or idea that is being discussed, but the theme actually says something about the subject.
John Donne's poem "Death Be Not Proud" provides a good example. In this poem, the writer is discussing the topic of death, but his theme says something very specific about death as well: that people who worship God don't need to fear death. (As you read this poem, don't be confused by the strange spellings. Try reading it out loud and just pronounce words the way they're written.)
Death be not proud, though some have called thee
Mighty and dreadful, for, thou art not so,
For those whom thou think'st, thou dost overthrow,
Die not, poor death, nor yet canst thou kill me.
From rest and sleep, which but thy pictures bee,
Much pleasure, then from thee, much more must flow,
And soonest our best men with thee do go,
Rest of their bones, and soul's delivery.
Thou art slave to fate, chance, kings, and desperate men,
And dost with poison, war, and sickness dwell,
And poppy, or charms can make us sleep as well,
And better then thy stroke; why swell'st thou then?
One short sleep past, we wake eternally,
And death shall be no more; Death, thou shalt die.
The main idea of a text is the thought that holds everything together. Likewise, the theme of a work of literature is the thought that holds together the characters and action. It's the idea that guides every choice that the writer makes throughout the text.
For example, look at the poem "A Poison Tree," from William Blake's Songs of Innocence and Experience. The poem has four stanzas (groups of lines in a poem, just as a paragraph is a group of lines in an essay or story).
I was angry with my friend:
I told my wrath, my wrath did end.
I told it not, my wrath did grow.
And I water'd it in fears,
Night & morning with my tears;
And I sunned it with smiles,
And with soft deceitful wiles
And it grew both by day and night,
Till it bore an apple bright.
And my foe beheld it shine,
And he knew that it was mine.
When the night had veil'd the pole;
In the morning glad I see
My foe outstretchd beneath the tree.
To understand Blake's theme, you need to look carefully at what happened and then look at why it happened. In the first stanza, Blake sets up two situations. First, the speaker (the voice or narrator of the poem) is angry with his friend (line 1) and he tells his friend about it (line 2). As a result, the anger goes away (line 2—my wrath did end). But he acts differently with his enemy. He doesn't tell his foe about his anger (line 4), and as a result, the anger grows (line 4).
In the second stanza, the speaker water'd his wrath in fears and sunned his wrath with smiles and wiles. Blake isn't being literal here; rather, he's drawing a comparison between the speaker's anger and something that grows with water and sun, like some kind of plant. How do you know exactly what it is? Blake tells you in two key places: in the title and in the last line. The poem is called "A Poison Tree," and tree is mentioned again in the last line of the poem.
This kind of comparison is called a metaphor, and it is an important clue to the meaning of the poem. Blake could have compared the speaker's anger to anything, but he chose to compare it to a tree. Trees have deep, strong roots and often flower or bear fruit. (This tree bears an apple.) They need some nurturing (sun and water) to grow.
In the third stanza, the foe sees the speaker's apple. In the fourth, he sneaks into the speaker's garden at night. Finally, at the end of the poem, the foe is killed by the poisonous apple (the apple poisoned by the speaker's wrath).
That is what happens in the poem, but what does it all add up to? What does it mean? In other words, what is the theme?
Look again at the action. Cause and effect are central to the theme of this poem. What does the speaker do? He tells his friend about his anger and chooses not to tell his enemy. What happens to his anger, then? It grows and grows and it offers fruit that tempts his enemy. And what happens to his enemy? He steals the apple, but it is the fruit of anger. It is poisonous and it kills him. Thus, the idea that best summarizes the idea of the poem is this: If you don't talk about your anger, it can be deadly. This is the message or lesson of the poem.
In many poems, the theme is an idea, while in others, the theme is an emotion. That is, the poet wants readers to feel an emotion very strongly. Poets can accomplish this through language. The next poem, written by Stephen Crane in 1899, combines both action and language to convey theme. Read the poem out loud at least twice.
A Man Said to the Universe
A man said to the universe:
"However," replied the universe,
"The fact has not created in me
Look carefully at the language in the poem. What kinds of words has the poet chosen? Are they warm, friendly words, or are they cold, distancing words? Do they make you feel comfortable and welcome, or uncomfortable and rejected? Are they specific or general? Do you feel like there's a personal relationship here, or are things formal and official?
Crane's word choice helps convey his theme. The words sir, fact, and obligation are cold and formal. There's no sense of personal relationship between the man and the universe. This is heightened by the general nature of the poem. It's just "a man"—not anyone specific, not anyone that you know—and not anyone that the universe knows, either. It's also written in third person; the poem would have a different effect if it began, "I said to the universe." The tone of the poem is cold and uncaring. That combined with action and word choice conveys Crane's theme: The universe is indifferent to humans.
Identifying Supporting Facts and Details
We've already touched on the topic of supporting details, and we've seen how identifying supporting details can actually help us to identify the main idea of a passage.
But on the GED, it will also be important to identify supporting details for other reasons, such as to learn certain facts or statistics that are stated by the writer. You will need to demonstrate that you know how to find specific information in a written passage, information that will focus on some small detail of the passage. This is different from being asked what the main idea is, because you will need to show that you understood some of the smaller details given in the passage.
Here is an example of a question dealing with supporting details.
The Difference between Fact and Opinion
You'll remember that the main idea, or thesis statement, of a piece of writing is very often a matter of opinion—something that can be debated and needs to be proven. You've also seen how supporting details are frequently statements of fact that are used to support that thesis or opinion. By looking at those differences, we have already covered the first step to seeing the difference between a fact and an opinion.
Facts are those things that we know for certain: dates when events occurred; whether or not something exists; names of people; and so forth. Opinions, however, are those things that might or might not be true: whether something is nice or pleasant; whether an event is good or bad; and so forth.
In the passage about car airbags you read earlier, the author gave you both facts and opinion. He stated the fact that people have been knocked unconscious by airbags, and you can determine whether or not this is a fact simply by doing some research. He also stated his opinion that airbags should be optional on cars, but this is not a fact that can be proven true or false by research; it is the opinion of the writer.
Words That Signal Opinions
We have considered some words and phrases that are often used when a writer presents facts, such as for example and specifically. In the same way, we can often recognize when an author is about to state an opinion by recognizing certain words and phrases that often accompany opinions.
Some words and phrases suggest moral obligation, words such as should and ought and must. For example, a passage might state that the government should not tax people for the necessities of life. This states an opinion because it is suggesting that the government has a moral obligation of some sort.
Other words express some form of personal judgment or evaluation. Such words include good, bad, better, worse, always, never, and many others.
Making Inferences
People often confuse the words imply and infer. You imply an idea by hinting at it without stating it directly. For example, you might tell a person that he's "on thin ice," by which you are implying that he's going to get into trouble if he doesn't change his behavior. The person who makes an implication is the person speaking or writing—not the person listening or reading.
When you infer an idea, on the other hand, you are the reader or listener—not the speaker or writer. The concept works in a similar manner: you infer an idea by taking a hint. More specifically, you take different pieces of information from the written passage and draw a new conclusion. For example, a book might tell you that "there was a strong sense of tension in the air as Mary entered the room." From this statement, you could infer that something is about to happen as Mary enters the room—even though the writer does not directly make that statement.
Implications and inferences are part of the more subtle art of communication, something that one cannot define by strict rules or signal words—yet we all understand how to imply things, and we all know how to recognize another person's implied statements. In verbal communication, we often imply things using subtle gestures or tone of voice—raising an eyebrow, leaving a sentence deliberately unfinished while gesturing with our hands, and many other techniques. By using these subtleties, we communicate to other people without directly stating what we mean, and we also infer another person's unspoken meaning by reading body language or listening to a tone of voice.
Written communication uses clues to communicate implied meanings, and you can learn to detect those clues simply by being on the lookout for them. Read each of the following practice passages, looking for clues to the writer's implied meanings. In this way, you will get the feel of how to infer.
Cause-and-Effect Relationships
Everything in life has both a cause and an effect. Rain is caused by water vapor in clouds that turns to liquid; rain has the effect of making things wet, watering plants, and so forth.
- cause: a person or thing that makes something happen or produces an effect
- effect: a change produced by an action or cause
You will be asked on the GED to identify certain causes or effects that are addressed in a piece of writing. These causes and effects may be either stated directly, or simply implied in the passage. If the passage clearly states, for example, that "World War I was caused by the assassination of Archduke Franz Ferdinand," then your job is fairly straightforward; you are merely being asked to look for supporting evidence which is clearly given in the passage.
On the other hand, you might be asked to find a cause or an effect—or both—from a passage that does not openly state them. In this case, you will need to bring in the inference skills you've just been developing. You will need to read what the author says directly, and then infer which thing caused something else, or what the effect was of some detail in the passage, or how one part of the passage has a cause-and-effect relationship with another part of the passage.
Sometimes you will be given a passage to read that does not directly discuss the causes or the effects of a given event, but merely discusses the event itself. You might then be asked to infer from the passage what caused the event, according to the author, or what effects the event produced.
Passages that discuss the cause of an event will generally be telling you why the event happened: Why did the cat climb the tree? For what reason did the chicken cross the road? Passages that discuss the effect of an event will generally be telling you what happened after the event: The fire department came (because the cat was in the tree). Traffic was tied up for an hour (because the chicken walked slowly).
This all may sound complicated, but it really isn't—it's a way of thinking and analyzing that we all do every day. Try a few for yourself and you'll quickly see that you already know how to look for causes and effects.
Understanding Words from Context
Everyone who reads will encounter words that are unfamiliar. The best way to learn a new word, of course, is to look it up in the dictionary. This will expand your vocabulary, and in time you will find that you rarely encounter words that you don't already know.
But even if you don't have a dictionary handy, you can still gain some idea of a word's meaning from the passage as a whole—which we call the context. Context refers to the meaning and ideas of a passage as a whole, as opposed to diction—the specific words and phrases used within the passage.
Read through the following passage and underline any unfamiliar words, or words that are used in unfamiliar ways. Don't use a dictionary just yet; see if you can determine the meanings just from the passage as a whole.
Television is a dangerous medium, because it shows the viewer artificialities and presents them as though they were real. An unsuspecting viewer can be so drawn into the television program that he forgets to remember that it is all make-believe. The images, sounds, actions; the characters, settings, plots—everything seems so very real that the average person gradually comes to believe that it is real. Other media, such as books and CDs, pose less of a threat to the average person, because one must engage one's mind to imagine what is described in writing or music. When we engage our imagination—indeed, when we engage our minds to any degree—we are less susceptible to the deceptions of fiction and drama. But television encourages the viewer to disengage his mind and just allow the actors to play out the story in front of him.
Look at the opening sentence: Television is a dangerous medium. The word medium, of course, is not unfamiliar; but perhaps you have never seen it used that way before. What exactly is a dangerous medium? But as you read on through the passage, you read the following: Other media, such as books and CDs… The context suggests that the author is comparing books with television, and he is calling them all "media." Media, of course, is another familiar word, and this time it is used in the way that we are all familiar with: to refer to television, radio, newspapers, and so forth. These are called media because they serve to provide something to consumers, just as a waiter provides food to the diner in a restaurant. The waiter is the medium, the middleman if you will, who is bringing the food to your table. In the same way, television is the device which brings news and programs into your home.
Perhaps you underlined susceptible. Again, the context of the passage can give you a good hint on the word's meaning. The main idea of the passage is that television takes advantage of a viewer by encouraging him to disengage his mind and believe that fictional programs are actually real. So in this context, susceptible would mean that, in some way, books and music do not take advantage of human weakness, while viewers of television run the risk of being caught when they are weak—which is essentially the meaning of susceptible.
Sometimes you can get enough context to understand a word just from the way that it's used in a sentence; other times, you'll need to dig out the meaning from the context of the entire passage. The above exercise shows you how to define words in context of the entire passage. Now practice a few, picking up the definitions just from the way that each word is used in a sentence.
Practice exercises for this study guide can be found at:
Reading Comprehension Practice Exercises: GED Language Arts, Reading
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