Our risk of cancer rises dramatically as we age. So it makes sense that the elderly should be routinely screened for new tumors — or doesn't it?

    While such vigilant(警觉的) tracking of cancer is a good thing in general, researchers are increasingly questioning whether all of this testing is necessary for the elderly. With the percentage of people over age 65 expected to nearly double by 2050, it's important to weigh the health benefits of screening against the risks and costs of routine testing.

    In many cases, screening can lead to additional biopsies(活检) and surgeries to remove cancer, which can cause side effects, while the cancers themselves may be slow-growing and may not pose serious health problems in patients' remaining years. But the message that everyone must screen for cancer has become so ingrained(根深蒂固的) that when health care experts recommended that women under 50 and over 74 stop screening for breast cancer, it caused a riotous reaction among doctors, patients and advocacy groups.

    It's hard to uproot deeply held beliefs about cancer screening with scientific data. Certainly, there are people over age 75 who have had cancers detected by routine screening, and gained several extra years of life because of treatment. And clearly, people over age 75 who have other risk factors for cancer, such as a family history or prior personal experience with the disease, should continue to get screened regularly. But for the remainder, the risk of cancer, while increased at the end of life, must be balanced with other factors like remaining life expectancy(预期寿命).

    A recent study suggests that doctors start to make more objective decisions about who will truly benefit from screening—especially considering the explosion of the elderly that will soon swell our population.

    It's not an easy calculation to make, but one that make sense for the whole patient. Dr. Otis Brawley said, “Many doctors are ordering these tests purely to cover themselves. We need to think about the rational(合理的) use of health care and stop talking about the rationing of health care.”

    That means making some difficult decisions with elderly patients, and going against the misguided belief that when it comes to health care, more is always better.

    I don't think there is anything more important than health. “Health is the greatest wealth，” wise people say. You can't be good at your studies or work well when you are ill.

    If you have a headache, toothache, backache, earache or bad pain in the stomach, if you complain of a bad cough, if you run a high temperature and have a bad cold, or if you suffer from high or low blood pressure, I think you should go to the doctor. The doctor will examine your throat, feel your pulse, test your blood pressure, take your temperature, sound your heart and lungs, test your eyes, check your teeth or have your chest X-rayed. After that, he will advise some treatment, or some medicine. The only thing you have to do is to follow his advice.

    Speaking about doctor's advice, I can't help telling you a funny story. An old gentleman came to see the doctor. The man was very ill. He told the doctor about his weakness, memory loss and serious problems with his heart and lungs. The doctor examined him and said there was no medicine for his disease. He told his patient to go to a quiet place for a month and have a good rest. He also advised him to eat a lot of meat, drink two glasses of red wine every day and take long walks. In other words, the doctor advised him to follow the rule: "Eat with pleasure, drink with pleasure and enjoy life as it is." The doctor also said that if the man wanted to be well again, he shouldn't smoke more than one cigarette a day. A month later the gentleman came into the doctor's office. He looked cheerful and happy. He thanked the doctor and said that he had never felt a healthier man." But you know, doctor," he said, “it's not easy to begin smoking at my age.”

    It's generally believed that people act the way they do because of their personalities and attitudes. They recycle their garbage because they care about the environment. They pay $5 for a caramel brulee latte because they like expensive coffee drinks.

    It's undeniable that behavior comes from our inner dispositions（性情）, but in many instances we also draw inferences about who we are, as suggested by the social psychologist Daryl Bern, by observing our own behavior. We can be strangers to ourselves. If we knew our own minds, why should we need to guess what our preferences are from our behavior? If our minds were an open book, we would know exactly how much we care about the environment or like lattes. Actually, we often need to look to our behavior to figure out who we are.

Moreover, we don't just use our behavior to learn about our particular types of character — we infer characters that weren't there before. Our behavior is often shaped by little pressures around us, which we fail to recognize. Maybe we recycle because our wives and neighbors would disapprove if we didn't. Maybe we buy lattes in order to impress the people around us. We should not mistakenly believe that we always behave as a result of some inner disposition.

Whatever pressures there can be or inferences one can make, people become what they do, though it may not be in compliance（符合）with their true desires. Therefore, we should all bear in mind Kurt Vonnegut's advice: “We are what we pretend to be, so we must be careful about what we pretend to be.”

    The World Health Organization says the widespread use of sugar in food products and drinks is a major concern in many areas. So WHO officials are calling on governments to require taxes on sugary drinks in an effort to limit their usage and popularity. The officials believe the taxes also would reduce the risk of health problems resulting from obesity.

    Obesity is a condition in which the body stores large, unhealthy amounts of fat. Obese individuals are considered overweight. A new report says that in 2014 more than one-third of the adults in the world were overweight, and 500 million were considered obese. The United Nations agency estimates that in 2015, 42 million children under age 5 were either overweight or obese. It says that number represents an increase of about 11 million during the past 15 years. Almost half of these boys and girls live in Asia and one-fourth in Africa.

    The U.N. agency blames unhealthy diets for a rise in diabetes cases. There are 422 million cases of the disease worldwide. WHO says 1.5 million people die from it every year. It says the use of sugar in food products, like sugary drinks, is a major reason for the increase in rates of obesity and diabetes.

    Temo Waqanivalu is with the agency's Department for the Prevention on Non-Communicable Diseases. He told VOA hat taxing sugary drinks would reduce consumption and save lives. Waganivalu noted that Mexico enacted a 10 percent tax on sugary drinks in 2014. He said by the end of the year, there was a 6 percent drop in the consumption of such drinks. Among poor people, the number of people who consumed sugary drinks dropped by 17 percent.

    The WHO says people should limit the amount of sugar they consume. It says they should keep their sugar intake to below 10 percent of their total energy needs, and reduce it to less than 5 percent for improved health.

    A new study shows that rising levels of planet-warming gases may reduce important nutrients in food crops.

    Researchers studied the effects of one such gas—carbon dioxide—on rice. The researchers grew rice plants in a controlled environment. They set carbon dioxide levels to what scientists are predicting for our planet by the end of the century. They found that the resulting rice crops had lower than normal levels of vitamins, minerals and protein. The researchers said the effects of planet-warming gases would be most severe for the poorest citizens in some of the least developed countries. These people generally eat the most rice and have the least complex diets, they noted.

    In the experiment, scientists grew 18 kinds of rice in fields in China and Japan. They pumped carbon dioxide gas over the plants in an effort to create the atmosphere of the future. Rice grown under high carbon dioxide conditions had, on average, 13 to 30 percent lower levels of four B vitamins and 10 percent less protein. The crops also had 8 percent less iron and 5 percent less zinc（锌）an rice grown under normal conditions. However, vitamin E levels increased by about 13 percent on average.

    The results are bad news, “especially for the nutrition of the poorer population in less-developed countries,” said the University of Tokyo's Kazuhiko Kobayashi, who helped to write the report. That includes about 600 million people in Indonesia, Cambodia, Myanmar, Bangladesh, Laos and other nations, mainly in Southeast Asia, the report said.

    One of the scientists is Sam Myers of Harvard University in the American state of Massachusetts. He said that findings like this are an example of the surprises climate change create. “My concern is there are many more surprises to come,” he said.

    Myers noted that pollution, loss of some species, destruction of forests, and other human activities are likely to produce unexpected problems. He said that you cannot completely change all the natural systems that living organisms have grown to depend on over millions of years without having effects come back to affect our own health.

    The new study suggests a way to lower the nutritional harm of climate change. One way, Kobayashi said, is grow different forms of rice that have shown to be more resistant to higher carbon dioxide levels.

    We all long for friendship, but how to make a friend? "The best time to make a friend is before you need one." Joy Steven said. The following are some tips for you.

    People equal friends

    Friends usually begin with strangers. Getting in touch with other people is the first step to make a friend. Friends can't be made in empty air. Best friends take time to make.

    Friends understand friends

    Friends understand each other when talking. Many unpleasant personal quarrels can be avoided if you will take the time to understand others' feelings and points of view.

    Friends touch friends

    Touching is a warm from of communication between friends. When you see best friends communicating, you will notice them stand close together, touch each other comfortably and listen to each other. Sometimes a friendly touch is more powerful than words.

    Friends praise friends

    Praise is a powerful tool to make a friend. Honest praise can affect (影响) your friends' lives. So try to praise your friends, including your general ones.

    Friends can loyal (忠诚的) and trustworthy

    Trust and loyalty go hand in hand for friends. Friends can share secrets with you, because good friends never break confidence (信心) and are loyal forever.