Main Ideas

ลำดับตอนที่ #5 : Exercise 05

Choose the best main idea for each selection

1. Bicycles are very popular today in many countries. Many people use bicycles for exercise. But exercise is only one of the reasons why bicycle are popular. Another reason is money. Bicycles are not expensive to buy. They do not need gas to make them go. They also are easy and cheap to fix. In cities, many people like bicycles better than cars. With a bicycle, they never have to wait in traffic. They also do not have to find a place to park. And finally, bicycles do not cause any pollution!

a. Bicycles do not cause the pollution.
            b. Bicycles are better than cars.
            c. Bicycles are popular today for many people.

2. It is important to bring the right clothes when you travel. If you are going
to a cold country, you should bring war, clothes. Be sure you have a hat and
gloves, too. If you are going to a hot country, you need different clothes.
You do not want heavy or dark clothes. In hot weather, light clothes are best!
If you are going to a city, you may need some nice clothes. You may want to
go to a special restaurant or a concert. It is different if you travel by
bicycle in the country. Then you will want comfortable clothes. But one rule
is the same for all travelers. Do not bring too many clothes!

            a. Clothes for warm weather are light.

            b. Clothes are important when you travel.
            c. Clothes can be heavy.

3. Cats and dogs are both popular pets. But cats are nice pets in some ways. Cats are cleaner first at all. They stay very clean and they do not make the house dirty. Cats are safer, too. Dogs sometimes bite people, but cats almost never do. And finally, cats are easier to take care of. You do not have to spend much time with a cat. In fact, many cats prefer to be alone.

            a. Some people prefer cats as pet.

            b. Cats do not make a lot of noise.
            c. Cats are nicer than dogs in some ways.

4. Many children want to have a pet. But parents do not like the idea of a dog or a cat in the house. In fact, pets can be good for children. A pet means something to play with. This can be especially important. If there is only one child. Also, children can learn a lot from a pet. They can learn about animals and the natural world. Children also learn about taking care of something. They cannot forget about their pet. This is an important lesson for all children.
            a. Children usually want a dog or a cat.
            b. Pets may be good for children.
            c. Parents sometimes do not like pets.

5. Most Americans think of cats as pets. But not all cats are pets. Some cats help people and other are a problem. For example, on farms and in old house, cats can help. They kill small animals such as rats or mice. But sometimes, people do not want cats around. Some people like to watch birds in their yards. Cats may kill the birds or scare them away. Cats are also a problem in cities. In Rome, for example, thousands of cats live in the streets and old buildings. They make a lot of noise, and they are dirty and dangerous.

            a. Cats can be a problem.
            b. Most Americans think of cats as pets.
            c. Cats are not just pets.

6. The earth is always changing. One way it changes is by erosion. Some is caused by the weather. For example, the wind causes erosion. In a desert, the wind blows the sand around. Rain also causes erosion. It washes away earth and even changes the shape of some rocks. Another kind of erosion is caused by rivers. When a river goes through a mountain, it cuts into the mountain. After a long time, the mountain is lower and the land is flatter.
            a. Rain causes erosion.
            b. Mountains change after a long time.

            c. Erosion changes the earth.

7. Mt. Vesuvius in Italy and Mt. St. Helens in the United States are both famous
mountains. They are both volcanoes. A volcano is a mountain that is open at
the top. Smoke and hot air come out of the hole. Sometimes very hot rock also
comes out of the mountain. That can mean trouble for people nearby. This is
what happened with Mt. Vesuvius and Mt. St. Helen. Hot rock poured out of
Mt. Vesuvius and cover the town of Pompeii in 79 AD. Everyone in the town
was killed. The Mt. St. Helens volcano did not kill many people. There were
no cities close to the mountain. But the hot rock killed a large part of the
forest. And a lot of dirt fell on cities many miles away.
            a. A volcano is a mountain with a hole on the top.

            b. Mt. Vesuvius and Mt. St. Helens volcanoes both caused trouble.
            c. Volcanoes can be dangerous.

8. Scientists know a lot about the earth. For example, they understand how mounatins are made and what a volcano is. But they do not know when a volcano will send hot rock into the air. They may know about the outside of the earth. But they still are not sure about the inside. And scientists are not sure about how the earth was made. They have many different ideas about this. There are still many difficult questions for scientists who study the earth.

            a. Scientists have different ideas about how the earth was made.
            b. Scientists now know a lot about them.
            c. Scientists still have many questions about the earth.

เฉลย : c, b, c, b, a, c, b, c