15000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 10)

Millions of people are using cellphones today. In many places, it is actually considered unusual not to use one. In many countries, cellphones are very popular with young people. They find that the phones are more than a means of communication - having a mobile phone shows that they are cool and connected.

The explosion in mobile phone use around the world has made some health professionals worried. Some doctors are concerned that in the future many people may suffer health problems from the use of mobile phones. In England, there has been a serious debate about this issue. Mobile phone companies are worried about the negative publicity of such ideas. They say that there is no proof that mobile phones are bad for your health.

On the other hand, medical studies have shown changes in the brain cells of some people who use mobile phones. Signs of change in the tissues of the brain and head can be detected with modem scanning equipment. In one case, a traveling salesman had to retire at young age because of serious memory loss. He couldn't remember even simple tasks. He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day, every day of his working week, for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't agree.

What is it that makes mobile phones potentially harmful? The answer is radiation. High-tech machines can detect very small amounts of radiation from mobile phones. Mobile phone companies agree that there is some radiation, but they say the amount is too small to worry about. As the discussion about their safety continues, it appears that it’s best to use mobile phones less often. Use your regular phone if you want to talk for a long time. Use your mobile phone only when you really need it. Mobile phones can be very useful and convenient, especially in emergencies. In the future, mobile phones may have a warning label that says they are bad for your health. So for now, it's wise not to use your mobile phone too often.

Most people think that lions only come from Africa. This is understandable because in fact most lions do come from there but this has not always been the case. If we went back ten thousand years. we would find that there were lions roaming vast sections of the globe. However now, unfortunately only a very small section of the lion’s former habitat remains.

Asiatic lions are sub-species of African lions. It is almost a hundred thousand years since the Asiatic lions split off and developed as a sub-species. At one time the Asiatic lion was living as far west as Greece and they were found from there, but in a band that spreads east through various countries of the Middle East, all the way to India. In museums now, you can see Greek coins that have clear images of the Asiatic lion on them. Most of them are dated at around 500 B.C. However, Europe saw its last Asiatic lions roaming free to thousand years ago. Over the next nineteen hundred years the numbers of Asiatic lions in the other areas declined steadily, but it was only in the nineteenth century that they disappeared from everywhere but in India.

The Gir Wildlife Sanctuary in India was established especially to protect the Asiatic lion. There are now around three hundred Asiatic lions in India and almost all of them are in this sanctuary. However, despite living in a sanctuary, which makes them safe from hunters, they still face a number of problems that threaten their survival. One of these is the ever-present danger of disease. This is what killed more than a third of Africa’s Serengeti lions in 1994, and people are fearful that something similar could happen in the Gir Sanctuary and kill off many of the Asiatic lions there. India’s lions are particular vulnerable because they have a limited gene pool. The reason for this is interesting – it is because all of them are descended from a few dozen lions that were saved by a prince who took a particular interest in them. He was very healthy, and he managed to protect them otherwise they would probably have died out completely.

When you see the Asiatic lion in India, what you sense is enormous vitality. They are very impressive animals and you would never guess that they this vulnerability when you look at them.

If you enjoy water sports, Hawaii is the place for you. You can go swimming all year round in the warm water. You can go sport fishing from the shore or from a boat. If you like boats, you can go sailing, canoeing, or windsurfing. Or, you can also try some other water sports that are especially popular in Hawaii. surfing, snorkeling and scuba diving.

Surfing is a sport which started in Hawaii many years ago. The Hawaiians called it “he’e nalu”, which means “to slide on a wave”. If you want to try surfing, you need, first of all, to be a good swimmer. You also have to have an excellent sense of balance. You must swim out from the beach with your surfboard under your arm. When you get to where the waves begin to break, you wait for a calm moment. Then you try to stand up on the board. The wave will begin to rise under you. You must try to steer the board with your feet so you stay on top of the wave. The important thing is to keep your balance and not fall down. If you can manage this, you will have an exciting ride all the way in to the shore.

Scuba diving and snorkeling are two ways to get a close look at the beauty lying below the surface of the ocean. The waters off the Hawaiian Islands are clean, clear and warm. They contain hundreds of kinds of colorful fish. The undersea world is made even more colorful by the coral reefs of red, gold, white and light purple. Among these reefs there may be larger fish or sea turtles. Scuba diving allows you to see the most interesting undersea sights. “Scuba” means “Self- contained Underwater Breathing Apparatus”, that is, equipment for breathing and swimming around far under water. In Hawaii, you can take special courses to learn how to scuba dive. After the courses, you can get a certificate that will allow you to dive alone. Since it can be dangerous, proper instruction and great care are always necessary when you are scuba diving.

If you are adventurous, you might try snorkeling instead of scuba diving. Less equipment is needed, just a face mask, a breathing tube (snorkel) and flippers for your feet. It only takes a few minutes to learn how to snorkel. Although you cannot dive deep into the water, you can swim with your face below the surface. Breathing through the tube, you float on the surface, and keep yourself moving with your flippers. Even from the surface like this, there will be plenty of color and beauty to see.