THE PARAGRAPH 37 THE PARAGRAPH 37

THE PARAGRAPH 37 THE PARAGRAPH 37

Air pollution has many effects on living organisms. Air pollution has three crucial effects on human health.

You can easily identify the differences between the underlined controlling ideas of the two sentences. You have probably noticed that it is possible to write a book (or some books) about the first sentence. You may have also noticed that the second topic sentence can be completely developed in a single paragraph.

When the topic sentence is loose, the writer may have to do one of the two things: (a) leave the paragraph incomplete, or (b) make the paragraph sketchy. An incomplete paragraph is one in which the topic sentence is not fully developed. A sketchy paragraph is one in which the supporting sentences are not clearly linked together. Such paragraphs suffer from abruptness or choppiness. In a choppy or sketchy paragraph, the writer jumps from one supporting sentence to another because he has to.

EXERCI SE

1. Consider the following paragraphs. Underline the topic sentence in

each paragraph. Circle the controlling ideas.

PARAGRAPH 1

There are two common kinds of telephone transmitters: the carbon transmitter and the electret transmitter. The carbon transmitter is made by placing carbon between metal plates. One of the metal plates is thin and takes changes in pressure caused by sound waves. I t transmits these changes to the carbon. The electrodes pass electricity that flows through the carbon. Changes in pressure caused by sound change the electrical resistance of the carbon. As a result, sound is transmitted.

38 THE PARAGRAPH

PARAGRAPH 2

Trees have many uses. Wood or lumber from trees is the most widely used material in the building of homes and other structures. Many trees give fruits and nuts such as oranges, grapefruits, apples, peaches, and almonds. Trees and their fruits are also the source of many oils, including olive oil and coconut oil. Tree trunks are used in making many products such as rubber. The barks of certain trees are sources of cork and spices. Many trees give important medicines. The bark of the yew tree is the source of the drug taxol, which from 1992 is used for treating ovarian cancer.

PARAGRAPH 3

Large rivers are located on every continent. The longest river on Earth is the Nile River in Africa. I t has a length of 6,695 km from its headwaters in Burundi to its mouth at the Mediterranean Sea. The Nile River basin covers an area of 3,349,000 square kilometers. The Amazon River in South America carries the largest amount of water. I t has a length of 6,400 km. This single river contributes 20 percent of the river water that flows into the world’s oceans. The Yellow River in China gets its name from the yellow soils of central China. I t carries the largest amount of soil to the ocean. The Yellow River is the second longest river in China. I ts length is 5,500 km. Yangtze, another river in China, has a length of 6,300 km.

Now answer the following questions:

1. What should you, the reader, expect the paragraphs to be about?

2. What questions will you expect to be answered in the paragraphs?

3. What specific details make each paragraph interesting for the reader?

4. Which details do you remember after reading each paragraph?

5. Are any of the paragraphs sketchy and choppy? Which one(s)?

6. Is the information in each paragraph related to its topic sentence?

7. Is each paragraph only about one topic?