I. What is a supporting sentence?
A supporting sentence is a sentence with information that supports a main idea or claim. Supporting sentences give a reader details to understand a main idea, or evidence to show why a claim is true or correct. You will find supporting sentences in the middle of a paragraph – after the topic sentence, and before a concluding sentence or transition.
II. Examples of a supporting sentence
Let’s consider the following main idea:
Modern automobiles are powered by combustion engines.
A writer who wants to explain this idea to readers must support it with information. The following supporting sentences can be used:
- a) A combustion engine is an engine that burns fuel to create power.
- b) The combustion engine replaced horses because they are more powerful and easier to maintain.
- c) Combustion engines allow us to travel quickly and safely in the comfort of our own cars and trucks.
Each of these sentences supports the main idea by giving the reader information or context to help understand the writer’s focus. Note that a writer would not use all three of these supporting sentences together. Choosing the best supporting sentence depends on what the writer is trying to achieve in the paragraph.
Here is a claim made by a writer:
Schools should start later in the day.
This is a claim that needs to be supported by facts (or perhaps opinions) in order to convince the reader to accept the claim. Here are some possible supporting sentences:
- a) Studies have shown that teenagers need more sleep than both younger children and adults because their rapidly changing bodies need more time resting in order to develop properly.
- b) By starting later, school busses can avoid the traffic of rush hour, which saves time and reduces the likelihood of accidents.
- c) Starting later will give students time to eat a healthy breakfast, which has been proven to improve school performance.
These supporting sentences each give evidence that help the reader agree with the writer’s claim. Again, a writer would not use all three of these supporting sentences together. Choosing the best supporting sentence depends on what the writer is trying to achieve in the paragraph.
III. Parts of a supporting sentence
The information in a supporting sentence depends on the type of support needed. Supporting sentences will include one of the following as their main parts:
- Descriptions or details
No matter what kind of supporting sentence you find, you will see that the main part of the sentence will be descriptions/details, facts, or examples. In section IV, (below) we will look at each of these types in more detail.
IV. Types of supporting sentences
a. Providing useful details
This type of supporting sentence is used when the writer wants to describe a main idea in more detail. It may be that the idea is complicated or new to the reader. It may also be used when the writer wants to add sensory descriptions to a piece.
Antarctica is a dangerous and lonely place. It is the coldest and driest continent on the planet. It is far away from hospitals and food supplies. Unpredictable weather can cause sudden blizzards which can trap people beneath several feet of snow in a matter of hours.
The first sentence is a topic sentence. Note how the next three supporting sentences each give details to help the reader understand why Antarctica is a dangerous and lonely place.
b. Presenting facts or evidence
High fructose corn syrup is bad for your health. It has been linked to the obesity epidemic, mostly because of its use in soft drinks. It is also digested by your body more quickly than natural sugars, and puts a tremendous strain on your liver. Consuming high amounts of high fructose corn syrup can also cause inflammation of the intestines, diabetes, and heart disease.
In this paragraph, the first sentence claims that high fructose corn syrup is bad for you. The next three sentences are supporting sentences – they each provide facts to support the writer’s claim.
c. Providing examples
American culture truly is a melting pot of cultures from around the world. As groups of people immigrate here they bring with them bits of their home culture, which are adopted by Americans and made part of American life. An obvious example is the amazing variety of ethnic foods that Americans enjoy. Pasta dishes from Italy, salsa from Mexico, and sushi from Japan have all become part of America’s dining culture. Another example is the sports and games we play. Martial arts from Asia are now a big part of American culture; soccer (football) has come from England and western Europe to be another part of American culture. Even the board games we enjoy, like chess and Parcheesi, arrived in America from India. Look around at all the wonderful things that Americans enjoy, and you will find that many of them were brought here by immigrants from around the world.
In this example, the writer states that American culture is made up of cultural elements from around the world. The supporting sentences that follow each give examples of these cultural elements so that the reader can see what the writer is trying to express.
V. How to write a supporting sentence
Remember, the topic sentence is what you are trying to express, and the supporting sentences are there to be sure that the reader understands your message. So, supporting sentences depend on your topic.
The type of supporting sentence you use will also depend on the type of essay you are writing. A narrative or descriptive essay, for instance, would use supporting sentences that describe and give details. An argumentative or persuasive essay would rely on using use supporting sentences to give facts or evidence. An expository essay would need to use plenty of supporting sentences that provide examples. No matter what kind of essay you are writing, keep in mind the following tips:
a. Make sure connections are clear
Make sure the connection between the supporting sentence and the topic sentence is clear. Using transition phrases to begin your supporting sentences can make this connection clear.
Many countries are trying to find ways to use fewer fossil fuels. The biggest reason for this is because of their rising prices. Another important reason is because of the environmental damage that is caused from burning fossil fuels.
b. Only give the audience information they need
You need to consider how much your reader knows (or doesn’t know) about your topic so that you can provide useful supporting sentences. For instance, imagine you are writing an essay about the cardiovascular system. If your audience is made up of young students in grades 1-5, you will want to include supporting sentences that explain that the heart and lungs are the main organs. However, if your audience is made up of students in high school, they would already know this basic information; your supporting sentences may want to describe the different kinds of veins and arteries, or present facts about how the lungs capture oxygen from the air and release carbon dioxide. On the other hand, you would not want to include extra information about the digestive system or the brain. Adding extra information might only confuse the reader or distract them from the point you are trying to make.
c. Include ideas that build on each other
Use your supporting sentences together to build towards bigger ideas. Your sentences can support not only the main idea, but also each other. In the following example, see how each supporting sentence explains the one before it. Using supporting sentences in this way helps bring your reader to understand more complex ideas and unifies your essay into one cohesive work.
Burning fossil fuels causes global warming. This is because when coal and oil are burned, they release gasses such as carbon dioxide, methane, and ozone. These gasses are large (at least for molecules!), and fill our atmosphere. As a result, heat from the Earth cannot find its way as easily into space. Instead, it ‘collides’ with these molecules and is the heat energy is absorbed. As a result, our skies are filled with heated gasses, which raise the average temperature of our world.