Sun and Skin Cancer A) When Ellen was a teenager, she loved to be out in the summer sun. She ran, she worked in her garden. She would swim and sit by the pool for hours soaking up the sunshine. And she never got tired of hearing people tell her how great her tan (古铜色) looked. B) As Ellen got older, she continued to spend lots of time outdoors in the sun. By the time she was in her forties, Ellen's skin had developed a weathered look, with small wrinkles (tk. it). That was okay, but she also began to notice brown patches developing on her face and hands. Ellen saw a doctor and found out she had a relatively mild case of skin cancer. Ellen was lucky. Her cancer was detected early. With early treatment, she was completely cured. But Ellen had begun—late in life—to pay for all those years she had spent in the sun. Ellen isn't unusual. The athletic, bronzed bodies we see in magazine ads and TV commercials constantly sell the idea that a good tan means health, attractiveness, and fun. The result is that many people believe those ads. And they spend a lot of time in the sun—often just trying to get tan. That golden or bronze color may look nice, but skin doctors know that sitting in the sun until you are baked several shades darker is not such a hot idea. C) According to the National Cancer Institute, over 400,000 Americans can expect to get some form of skin cancer this year. Most of these people will be 40 or older. However, skin cancer—especially skin cancer caused by exposure to the sun—can often take many years to develop. So it's never too early to protect yourself in the sun. D) As soon as warm weather arrives, lots of people who don't already have dark skin want to start working on their tans. But a tan isn't really nature's way of making you look beautiful. A tan is your skin's defense against the sun's ultraviolet (紫外线的) radiation. UV rays damage skin cells. So when you decide to have a marathon roasting session in the sun, cells in your skin called melanocytes (黑素细胞) go to work overtime. They produce an extra supply of melanin (黑色素), the brown-black pigment (色素) that gives your skin its color. That extra melanin makes your skin darker, and that's why you "tan". E) Think of your tan as a shield of melanin your body produces to block out the UV radiation. The problem is, it's a weak shield at best. There's no way for your body to protect itself fully against the sun's harmful rays—especially if you expose yourself to the sun hour after hour, day after day, year after year. As you get older, the buildup of many hours in the sun means more of a chance for skin damage—and possibly skin cancer. F) This skin damage takes two general forms. Some UV attacks supporting cells in the lower layer of the skin, called the dermis (真皮). That causes skin to get dry, tough and wrinkled. Even more serious is the damage the sun's UV rays can do to the DNA of skin cells. DNA is the genetic blueprint that cells use to reproduce. With damaged DNA, the skin may produce mutated (变异) cells that start to grow in an uncontrolled way: skin cancer. G) Nature gives you a clue about how much sun is enough by the color of your skin. If your skin is light, you don't have much built-in protection against the sun. You probably tan very little, if at all. So be very careful in the sun. If you have dark skin and dark hair, you can probably stand a bit more sun exposure. Just don't be fooled into thinking you can stay out in the sun indefinitely. You can't. People with dark skin also get sunburned and can suffer skin damage. It just takes a bit longer for the damage to show up. H) The three most common types of skin cancer are all connected with exposure to the sun. The most common of these is basal cell carcinoma. Basal cancers often look like wax-like growths or red, scaly (有鳞的) patches. They appear most often on the face, neck, or hands. Squamous (有鳞片的) cell cancer is the second common type. This cancer spreads more quickly. Squamous cell cancers often appear on the head, hands, or other sun-exposed parts of the body. They show up as sharply outlined red, scaly patches. The third type of skin cancer is called melanoma (黑素瘤). Melanoma is often caused by too much exposure to the sun, but it can be brought on by other things as well. Melanoma show up as brown or black mole-like (像痣的) growths on the back and legs. They can also appear on the palms, fingers, and toes. Melanoma is the rarest of these three kinds of skin caner, but it is the most serious form. While the overwhelming majority of basal and squamous cell cancer cases can be cured, many melanoma cases are fatal. I) Since all of these forms of cancer can resemble harmless skin marks of irritations, be aware of marks of growths on your skin. And consult a doctor if you notice any changes. "In general, look for anything new in your skin," advises skin doctor, Dr. Louis Vogel. "Pay attention to anything on your skin that grows rapidly, that bleeds or has irregular color. Also, suspect any mole that itches (发痒) or has some areas that are darker or higher than others." J) Although skin cancer is the most common form of cancer, it is also the most treatable—if caught early. There are several methods of treatment. They include surgical removal, treatment with heat, extreme cold and freezing, as well as chemical treatment and use of X-rays. However, as with many other diseases, the most important "cure" is prevention. "Cover as much skin as possible when you are out in the sun," warns Dr. Vogel. "When you are at the beach, wear sun blocks. There are many things in life you can't prevent. But skin cancer is something you can often prevent if you take the proper precautions."

The National Trust in Britain plays an increasingly important part in the preservation for public enjoyment of the best that is left unspoiled of the British countryside. Although the Trust has received practical and moral support from the Government, it is not a rich Government department. It is a charity which depends for its existence on voluntary support from members of the public. The attention of the public was first drawn to the dangers threatening the great old houses and castles of Britain by the death of Lord Lothian, who left his great seventeenth-century house to the Trust together with the 4,500-acre park and estate surrounding it. This gift attracted wide publicity and started the Trust's "Country House Scheme". Under this scheme, with the help of the Government and the general public, the Trust has been able to save and open to the public about one hundred and fifty of these old houses. Last year about one and three quarters of a million people paid to visit these historic houses, usually at a very small charge. In addition to country houses and open spaces the Trust now owns some examples of ancient wind and water mills, nature reserves, five hundred and forty farms and nearly two thousand five hundred cottages or small village houses, as well as some complete villages. In these villages no one is allowed to build, develop or disturb the old village environment in any way and all the houses are maintained in their original sixteenth-century style. Over four hundred thousand acres of coastline, woodland, and hill country are protected by the Trust and no development or disturbances of any kind are permitted. The public has free access to these areas and is only asked to respect the peace, beauty and wildlife. So it is that over the past eighty years the Trust has become a big and important organization and an essential and respected part of national life, preserving all that is of great natural beauty and of historical significance not only for future generations of Britons but also for the millions of tourists who each year invade Britain in search of a great historic and cultural heritage.

Only special plants can survive the terrible climate of a desert, for these are regions where the annual range of the soil temperature can be over 75°C. Furthermore, during the summer there are few clouds in the sky to protect plants from the sun's ray. Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants, tearing and damaging them. The most difficult problem for all forms of plant life, however, is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long, hot, dry season in the form of seeds. These seeds remain inactive unless the right amount of rain falls. If no rain falls, or if insufficient rain falls, they wait until the next year, or even still the next. Another factor that helps these plants to survive is the fact that their life cycles are short. By the time that the water from the spring rains disappears—just a few weeks after it falls—such plants no longer need any. The perennials (多年生植物) have special features which enable them to survive as plants for several years. Thus, nearly all desert perennials have extensive root systems below ground and a small shoot system above ground. The large root network enables the plant to absorb as much water as possible in a short time. The small shoot system, on the other hand, considerably limits water loss by evaporation (蒸发). Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long, dry season, just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season. Then, in the next rainy reason, they come fully alive once more, and grow new branches, leaves and flowers, just as the grasses and flowers in desert do.