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Text 2 Bacteria are microscopic organisms which live on the surface of objects. They are one of the most ancient living things, which exist on this planet for nearly 4,000 million years. Do you know the size of bacteria It can only be measured in microns. Maybe you have not a standard in your mind how long a micron is. One micron is a thousandth of a millimeter, which equals about the diameter of a pinhead. Therefore, even if we enlarged the rounded bacterium a thousand times, it would only be the size of a pinhead. We barely see bacteria by a magnification an ordinary microscope of 100 times, even if we try, we cannot make out anything of their structure. There are normally millions of them together, for they can multiply really fast. Scientists have found that some bacteria have attached to wavy-looking "hairs" called flagella. The flagella rotate, pushing the bacteria through the water. Others can glide along over surfaces by some little-understood mechanism. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. They are active all the time. Even the bacteria without flagella often bound about in the water. They are pushed here and there, colliding with the watery molecules. Bacteria cannot be detected because they don’t produce bad odor or change the color or texture of the food. Therefore, when people eat the food with many bacteria, they are likely to get hepatitis A, acute gastroenteritis and a host of other illnesses. Many households have refrigerators to prevent from bacteria. Of course, freezing food slows or stops the growth of bacteria, however, when food is thawed, the bacteria will become reactivated. Bacteria can not be totally destroyed before the food is thoroughly cooked. We need to know that not all bacteria are in connection with illness. Just some bacteria can cause disease. They are called pathogenic bacteria. Fortunately our immune system can protect us from them. Bacteria are prokaryotes ( single cells that do not contain a nucleus). It may seem weird to classify organisms according to such details, but with or without a nucleus is not trivial at all. The division between prokaryotes and eukaryotes (all organisms with a nucleus inside their cells) is of extreme importance in biology, and is the result of a major evolutionary breakthrough. Visit our program tomorrow if you want to know more, thank you. What can be inferred from the last paragraph

A. Whether or not to have a nucleus is important in biology.
B. The speaker will tell us how to distinguish bacteria tomorrow.
C. Evolution will be the main topic of the program next time.
D. Eukaryotes develop from prokaryotes.

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Part A Read the following four texts. Answer the questions below each text by choosing [A], [B], [C] or [D]. Mark your answers on ANSWER SHEET 1.Text 1 We often hear advice from the dermatologists, "You should keep using sunscreen cream--just to be safe". More and more people are questioning about sunscream. Can sunscreen cream help protect me against melanomas How safe are we in applying these chemical cocktails Does it actually stop melanomas, the most dangerous type of skin cancer, from forming As is known to all, sunscreen cream can protect the skin from the harmful effects of sun. The most .important function of it is the prevention of skin cancer. A great number of American people like to use it. Surprisingly, this kind of cancer is increasing in incidence faster than any other cancer in the United States. It seems that sunscreen actually increases the risk of skin cancer. More and more health experts are taking a discommendable attitude to the application of sunscreen. Researchers show that the earlier finding has many flaws and is unable to prove the exact function because they fail to take into account many exceptional cases. For instance, some people prefer to use sunscreen cream while going out. However, sunscreen cream users suffer from cancer more often. In fact, sunscreen cream allows people to remain exposed in the sun longer. People are likely to get skin problem under the sunshine for a long time. Besides, many people use the sunscreen cream in an inappropriate way. The sunscreen cream should be applied about half an hour before going outside, so the time is enough for the sunscreen to soak in and take effect. In fact, the protection of sunscreen will not last indefinitely. It should be reapplied at least every two hours when people stay outdoors for a prolonged period. After swimming, bathing, perspiring heavily, or drying off with a towel or handkerchief, you had better reapply it, too. Millions of gallons of sunscreen cream are consumed each year. Only 5% of products overall met the criteria for safety and sunscreen effectiveness. Three of five brand-name products can not protect the skin from sun damage sufficiently or they contain hazardous chemicals, according to a report by Environmental Working Group (EWG). It is time to change our misunderstanding now. In fact, besides the sunshine-preventing function, it also has the function of protecting our skin. We all know that the sun impacts collagen production in the skin, and without collagen, skin won’t naturally maintain that plump, moist, youthful, wrinkle-free look. Without the protection of sunscreen cream, just a few minutes of daily sun exposure over the years can cause noticeable changes in skin. Sunscreen cream can protect our skin from these damaging rays, so that even if we do spend time outdoors, our face is less likely to give away our age. What is mainly discussed in the text

A. How to use sunscreen cream better
B. The different opinions on sunscreen cream
Connection between cancer and sunscreen
D. Research on the new functions of sunscreen cream

Text 3 As the volcano erupts in Iceland, more and more people are beginning to concern about the damage volcanic eruption brings. Then, let us learn the influence of volcanic eruption together. We all know that air pollution has an effect on the world’s average air temperature. Scientists declare that volcanic eruption leads to weather changes, which is similar to air pollution. How will volcanic eruption impact on weather Volcanic eruption throws hundreds of millions tons of ash into the stratosphere. The ash from a volcano spreads in a few days. However, this is not the end. The ash will remain in the air for years. Hereby, all the ash turns incoming solar radiation into space, which cools the earth. The eruption would affect every level of ecosystem, from worms to primates. The problem is not only the physical destruction of habitat, but also the sulfur gases over the area. The volcanic eruption makes many people homeless who have to search for food and residence everywhere. The movement of the population and refugees may lead to some instability in the region. They may become one part to damage the environment in face of starvation threat. If the lava pours into lakes, the water will be severely contaminated. The unusual accumulation of carbon dioxide in the lower strata of lake’s basin may even cause explosions. The volcanic eruption is a huge disaster for human beings. It will cause massive dislocation in the local place. The Iceland volcano is a good example. More than 63,000 flights had been canceled in 23 European countries, which is severe blow on the economy. Travelers had to give up their journeys. Fresh foods get decayed because of delayed transportation. The factories are not able to operate for lack of machinery parts. In other parts of the world, people canceled their flights to and from Europe, according to the Air Transport Association (ATA). This condition has an awful influence on the world economy. Large quantities of dust and gaseous material will be injected into the upper atmosphere as a result of explosive eruptions. The volcano spurts a kind of glassy material with sharp edges, which is cooled by tiny shards of molten rock. The air is mixed with such material at a microscopic level. As a result, it will contribute to a worldwide rise in deaths of respiratory diseases. According to the whole passage, how many aspects are referred as for volcanic eruption’s influence

A. 5
B. 6
C. 4
D. 3

Text 2 Bacteria are microscopic organisms which live on the surface of objects. They are one of the most ancient living things, which exist on this planet for nearly 4,000 million years. Do you know the size of bacteria It can only be measured in microns. Maybe you have not a standard in your mind how long a micron is. One micron is a thousandth of a millimeter, which equals about the diameter of a pinhead. Therefore, even if we enlarged the rounded bacterium a thousand times, it would only be the size of a pinhead. We barely see bacteria by a magnification an ordinary microscope of 100 times, even if we try, we cannot make out anything of their structure. There are normally millions of them together, for they can multiply really fast. Scientists have found that some bacteria have attached to wavy-looking "hairs" called flagella. The flagella rotate, pushing the bacteria through the water. Others can glide along over surfaces by some little-understood mechanism. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. They are active all the time. Even the bacteria without flagella often bound about in the water. They are pushed here and there, colliding with the watery molecules. Bacteria cannot be detected because they don’t produce bad odor or change the color or texture of the food. Therefore, when people eat the food with many bacteria, they are likely to get hepatitis A, acute gastroenteritis and a host of other illnesses. Many households have refrigerators to prevent from bacteria. Of course, freezing food slows or stops the growth of bacteria, however, when food is thawed, the bacteria will become reactivated. Bacteria can not be totally destroyed before the food is thoroughly cooked. We need to know that not all bacteria are in connection with illness. Just some bacteria can cause disease. They are called pathogenic bacteria. Fortunately our immune system can protect us from them. Bacteria are prokaryotes ( single cells that do not contain a nucleus). It may seem weird to classify organisms according to such details, but with or without a nucleus is not trivial at all. The division between prokaryotes and eukaryotes (all organisms with a nucleus inside their cells) is of extreme importance in biology, and is the result of a major evolutionary breakthrough. Visit our program tomorrow if you want to know more, thank you. What is the meaning of "collide" in the second paragraph

A. strike
B. connect
C. bounce
D. mix

Directions: You will hear three dialogues or monologues. Before listening to each one, you will have 5 seconds to read each of the questions which accompany it. While listening, answer each question by choosing A, B, C or D. After listening, you will have 10 seconds to check your answer to each question. You will hear each piece once only. Questions 11—13 are based on the following passage. You now have 15 seconds to read Questions 11—13. What can be inferred from the passage

A. 11 percent of boys in America smoke before their fourth grade.
B. Nicotine is a part of cigarette.
Children form values in the fourth grade.
D. Parents who cannot stop smoking should force their children to stay away from it.

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