Supporting Ideas
4. Supporting ideas answer the question. “What makes the main idea believable?” Most of the sentences in a well-written passage contain supporting ideas that explain, illustrate, describe, or develop the main idea. These ideas strengthen and support the main idea.
Some TOEFL questions ask you to recognize how supporting ideas relate to the main idea. Look at some examples:
Which of the following statements does the passage support?
The passage supports all of the following statements EXCEPT
The above questions are really asking you to identify the main idea. You are likely to get this type of question when the main idea is not stated directly in the passage.
Note: In a question like The passage supports all of the following statements EXCEPT..., three of the answer choices will be true according to the passage. However, the correct answer is the one choice that is not true or not dealt with in the passage.
Look at main and supporting ideas in the following passage:
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Snow consists of large and often complex crystals that originate in the clouds. When snowflakes form in significant number and become heavy enough to fall from the clouds, a snowstorm is born. Although snowstorms can cause damage, they also help sustain human, animal, and plant life.
Snow is of tremendous importance in air climate patterns, and it has a major effect on our daily lives. Perhaps the best way to appreciate the significance of snow is to consider what happens when it fails to fall in places that rely on it. Snow provides water for forests, agriculture, industry, and drinking. In California, for instance, most of the water for irrigation comes from snow melt. Also, insulating and reflective snow cover on the ground can affect the global climate and the local weather.
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The main idea is snowstorms help sustain human, animal, and plant life. Ideas that support this statement are shown in italics.
There are other ideas in the passage—snow originates in clouds, snow and cause damage—but these ideas do not control the passage. Rather, they provide background about the topic.