Toefl exam Essentials

The Everglades National Park is the largest
remaining subtropical wilderness in the continental
United States. Where would this sentence best fit in the
paragraph? Click on the square (
■) to add the sentence
to the paragraph.

---

READING
91
LOCATING THE MAIN IDEA
Writing is communication—a writer tries to convey his thoughts
to a reader through words. When standardized tests ask you to
find the main idea of a passage, they are asking you to uncover
the writer’s motive, or why she wrote what she did.
To determine the main idea of a passage, think about a gen-
eral statement that brings together all of the ideas in a paragraph
or passage. Do not confuse the main idea of a passage with its main
topic. The topic is the subject—what a passage is about. The main
idea is what the author wants to express about the subject. To pre-
sent a main idea, many textbook writers follow the basic format
of general idea 
→ specific support. First, they state their main
idea and then provide support for it with specific facts and details.
A first sentence may contain a main idea. However, sometimes
an author builds up to her point, in which case you may find the
main idea in the last sentence of the introductory paragraph or
even the last sentence of the entire passage.
Practice
Read the passage and then answer the following question.
Space shuttle astronauts, because they spend only about a week
in space, undergo minimal wasting of bone and muscle. But
when longer stays in microgravity or zero gravity are contem-
plated, as in a space station or a two-year roundtrip voyage to
Mars, these problems are of particular concern because they could
become acute. Fortunately, studies show that muscle atrophy can
be kept largely at bay with appropriate exercise. Unfortunately,
bone loss caused by reduced gravity cannot.

---

92