For some people, music is no fun at all. About four percent of the population is what scientists call "amusic." People who are amusic are born without the ability to recognize or reproduce musical notes (音调). Amusic people often cannot tell the difference between two songs. Amusics can only hear the difference between two notes if they are very far apart on the musical scale.

As a result, songs sound like noise to an amusic. Many amusics compare the sound of music to pieces of metal hitting each other. Life can be hard for amusics. Their inability to enjoy music set them apart from others. It can be difficult for other people to identify with their condition. In fact, most people cannot begin to grasp what it feels like to be amusic. Just going to a restaurant or a shopping mall can be uncomfortable or even painful. That is why many amusics intentionally stay away from places where there is music. However, this can result in withdrawal and social isolation. "I used to hate parties," says Margaret, a seventy-year-old woman who only recently discovered that she was amusic. By studying people like Margaret, scientists are finally learning how to identify this unusual condition.

Scientists say that the brains of amusics are different from the brains of people who can appreciate music. The difference is complex, and it doesn't involve defective hearing. Amusics can understand other nonmusical sounds well. They also have no problems understanding ordinary speech. Scientists compare amusics to people who just can't see certain colors.

Many amusics are happy when their condition is finally diagnosed (诊断). For years, Margaret felt embarrassed about her problem with music. Now she knows that she is not alone. There is a name for her condition. That makes it easier for her to explain. "When people invite me to a concert, I just say, ‘No thanks, I'm amusic,'" says Margaret. "I just wish I had learned to say that when I was seventeen and not seventy." (335 words)

    If you get into the forest with your friends, stay with them always. If you don't, you may get lost. If you really get lost, this is what you should do. Sit down and stay where you are. Don't try to find your friends—let them find you by staying in one place.

    There is another way to help your friends or other nearby people to find you. Give them a signal (信号) by shouting or whistling (吹口哨) three times. Any signal given three times is a call for help.

    Keep up shouting or whistling always three times together. When people hear you, they will know that you are not just making noise for fun. They will let you know that they have heard your signal. They give you two shouts, two whistles, or two gun-shots (枪声). When someone gives you a signal, it is an answer to a call for help.

If you don't think that you will get help before night comes, try to make a little house—cover up to the holes with branches (树枝) with lots of leaves. Make yourself a soft bed with leaves and grass.

    What should you do if you get hungry or need drinking water? You would have to leave your little house to look for a river. Don't just walk away. Pick off small branches and drop them as you walk so that you can find your way back. The most important thing to do when you are lost is—stay in one place.

    September is an exciting month in every college freshman's life. For many, it's the first time that they've left home to live in a new environment. But after the hustle and bustle（喧嚣）of a few weeks, excitement gives way to a less enjoyable emotion— homesickness.

    Homesickness manifests（显露）itself in many ways. You may miss mum's cooking, your pets, or even your old bed. All this becomes a fond memory of the past. Homesickness can be a bitter feeling for many students, especially when faced with the challenges of settling into an unfamiliar environment.

    But remember, you're not alone. According to a recent BBC article, 70 percent of British college students experience homesickness. In this increasingly globalized world in which people migrate to faraway places for a relationship, education or work, homesickness is a feeling shared by many adults.

    Homesickness can have similar symptoms to depression and in extreme cases it can develop into a panic attack. As for the term, homesickness or nostalgia wasn't invented until the 17th century. It was considered a disorder by a Swiss physician, who attributed soldiers' mental and physical discomfort to their longing to return home, “nostos” from Greek, and the accompanying pain, “algos”.

    Studies in recent years, however, have shown that nostalgia may have some benefits to our mental health. After a decade of surveys and researches, Constantine Sedikides, a US social psychologist, found that nostalgia is what makes us human. He explains that nostalgia can resist loneliness, boredom and anxiety. Therefore, it's necessary for college students to learn some ways to overcome the uncomfortable feeling.

    Many people, both men and women in the world love drinking. The popular wisdom for years has been that drinking in moderation (适度) —that's one “standard” drink a day for women and two for men—is linked to a lower risk of cardiovascular (心血管的) disease. But recent studies are casting some doubt on that long-held learning. Science now says it depends on your age and drinking habits.

    A 2017 study of nearly 2 million British with no cardiovascular risk found that there was still a modest benefit in moderate drinking, especially for women over 55 who drank five drinks a week. Why that age? Alcohol can influence the substance in the blood in positive ways, experts say, and that's about the age when heart problems begin to occur.

    Also, a 2018 study found that drinking more than 100 grams of alcohol per week—equal to roughly seven standard drinks in the United States or five to six glasses of wine in the UK—surely increases your risk of death from all causes and in turn lowers your life expectancy. Links were found with different forms of cardiovascular disease, with people who drank more than 100 grams per week having a higher risk of stroke, heart failure.

    Another 2018 study found that consistently drinking moderately, within the recommended amount of alcohol, had a protective effect on the heart over time. Unstable drinking habits were associated with a higher risk of heart disease, which the authors reflected might indicate broader lifestyle changes, such as poor health or stress. Former drinkers were also at greater risk.

    Overall, however, the latest thinking is that any heart benefit may be outweighed by other health risks, such as high blood pressure, certain cancers and liver damage.

    Women who drink are at a higher risk for breast cancer; alcohol contributes about 6% of the overall risk, possibly because it raises certain dangerous hormones in the blood. Drinking can also increase the chance you might develop liver, mouth and oral cancers. One potential reason： Alcohol weakens our immune systems, making us more likely to inflame (发炎)—a driving force behind cancer.

Doing crosswords(纵横字谜) is a fun way to kill the time and can also be educational. Difficult crosswords may leave you confused as you have no ideas on how to solve them sometimes. To perform well in this game, you need to have enough knowledge of different fields. If you are unable to do them and you have access to the answers, it is not generally considered cheating to look up an answer or two. However, in some cases, it does not follow the rule.

A crossword should not include someone else's answers, so even a quick look at a fellow student to complete a crossword would not be fair. Generally, you wouldn't have access to the answers.

Additionally, some crossword competitions should not be connected with cheating. Again, in such a situation, you usually won't have access to the answers. Turning to the Internet or referring to(查阅) any books of crosswords for answers is also unfair, since some people will complete the crosswords strictly with their own knowledge.

If you are not in a competitive environment, the check of a word can actually be an opportunity to learn how to become better at crosswords. Through looking up the answers (Although sometimes considered as cheat.), you can memorize whatever facts or word definitions (定义) you must look up. This will help you avoid the need to cheat in the future.

Some argue that cheating on crosswords is always wrong, and you're only cheating yourself if you are looking up the answers. It could be argued instead that cheating on crosswords that are done for fun or enjoyment can actually be an opportunity to benefit yourself because you're learning something new. Just don't forget to mention that you actually did cheat a little. Being honest is of great importance both to you and the other competitors.

It can be helpful to buy books of crosswords that have several different difficulty levels. If you are new to doing crosswords, you might want to put off working on crosswords until you are more confident in your skills.

Scientists at the Department of Energy's Lawrence Berkeley National Laboratory and the California Institute of Technology have-in just two years-nearly doubled the number of materials known to have potential for use in solar fuels.

They did so by developing a process that promises to speed the discovery of commercially viable (商业可行性) generation of solar fuels that could replace coal, oil, and other fossil fuels.

Solar fuels, a dream of clean-energy research, are created using only sunlight, water, and carbon dioxide. Researchers are exploring a range of possible target fuels, but one possibility is to produce hydrogen by splitting water.

Each water molecule (分子) consists of one oxygen atom and two hydrogen atoms. The hydrogen atoms are extracted, and then can be reunited to create highly flammable hydrogen gas or combined with CO 2 to create hydrocarbon fuels, creating a plentiful and renewable energy source. The problem, however, is that water molecules do not simply break down when sunlight shines on them-if they did, the oceans would not cover most of the planet. They need a little help from a solar-powered catalyst (催化剂).

To create practical solar fuels, scientists have been trying to develop low-cost and efficient materials that perform the necessary chemistry using only visible light as an energy source.

A new method was developed through a partnership between the Joint Center for Artificial Photosynthesis (JCAP) and Berkeley Lab's Materials Project, using resources at the Molecular Foundry and the National Energy Research Scientific Computing Center (NERSCC). JCAP focused on developing a cost-effective method of turning sunlight, water, and carbon dioxide into fuel. It is led by Caltech with Berkeley Lab as a major partner. The Materials Project is a program based at Berkeley Lab that aims to remove the guesswork from materials design in a variety of applications.

"What is particularly significant about this study, which combines experiment and theory, is that in addition to identifying several new compounds for solar fuel applications, we can also learn something new about the basic electronic structure of the materials themselves." says Neaton, the director of the Molecular Foundry.