Red meat, usually considered to be beef, pork, mutton and lamb products, have nutritional value, but eating red meat also raises some health concerns.

    Red meat is an excellent source of protein(蛋白质). It is also a key source of vitamin B12, which is only available in animal products and is key for both red blood cell and nerve health. Red meat is also a rich source of zine, selenium(硒) andiron. Zinc and selenium are good for our immune system (免疫系统). Iron helps transport oxygen in the blood, and low levels of iron can lead to feeling tired. Eating red meat, especially lean cuts(廋肉), with meals and snacks, may help people curb hunger between meals and help people with weight management.

    Health risks of red meat may include the risk of heart disease and cancer. It is usually best to avoid processed meats. These tend to contain lots of salt and nitrites(亚硝酸盐), which may damage our health. Choosing lean cuts and cooking meat correctly may reduce health risks. It is generally advised not to undercook or overcook red meat and to avoid grilling(烧烤).

    When it comes to red meat and health, another thing is whether the animals are grain or grass-fed. Grass-fed animals frequently have a better quality of life. Grass feeding can be more environmentally friendly as well.

    Many governments suggest the amount of red meat should be safely included in a healthy diet. The amount varies between nations, but several portions a week are usually acceptable. Those who choose to include eating red meat may wish to choose grass-fed animals and to cut off any fat before eating.

Maths and Music

    An excellent way to kill a conversation is to say you are a mathematician. Tell others you are also a musician, however, and they will be hooked. Although there are obvious similarities between mathematical and musical activity, there is no direct evidence for the kind of magical connection many people seem to believe in.

    I'm partly referring here to the "Mozart effect", where children who have been played Mozart compositions are supposedly more intelligent, including at maths, than other children. It is not hard to see why such a theory would be popular: we would all like to become better at maths without putting in any effort. But the conclusions of the experiment that expressed the belief in the Mozart effect were much more modest. If you want your brain to work better, you clearly have to put in hard work. As for learning to play the piano, it also takes effort.

    Surely a connection is quite reasonable. Both maths and music deal with abstract structures, so if you become good at one, then it is likely that you become good at something more general that helps you with the other. If this is correct, it would show a connection between mathematical and musical ability. It would be more like the connection between abilities at football and tennis. To become better at one, you need to improve your fitness and coordination (协调). That makes you better at sport and probably helps with the other.

    Abstract structures don't exist only in maths and music. If you learn a language then you need to understand its abstract structures like grammar. Yet we don't hear people asking about a connection between mathematical and linguistic (语言的) ability. Maybe this is because grammar feels mathematical, so it wouldn't be surprising that mathematicians were better at learning grammar. Music, however, is strongly tied up with feelings and can be enjoyed even by people who know little about it. As such, it seems different from maths, so there wouldn't be any connection between the two.

    Let's see how we solve problems of the "A is to B as C is to D" kind. These appear in intelligence tests but they are also central to both music and maths. Consider the opening of Mozart's Eine Kleine Nachtmusik (小夜曲). The second phrase is a clear answer to the first. The listener thinks: "The first phrase goes upward and uses the notes of a G major chord (和弦); what would be the corresponding phrase that goes downward and uses the notes of a D7?" Music is full of puzzles like this. If you are good at them, expectations will constantly be set up in your mind. The best moments surprise you by being unexpected, but we need the expectations in the first place.

    Reintroducing beavers (海狸) to Britain could help clean up rivers, prevent flooding and minimise soil loss, an expert has claimed.

    Professor Richard Brazier, a researcher at the University of Exeter, said unpublished results from a trial area in Devon showed muddy water entering an area where beavers were living was three times cleaner when it left. "Our trial has shown that the beavers are able to dam our streams in a way that keeps soil in the headwaters of our catchment (流域) so it doesn't block up rivers downstream and pollute our drinking and bathing waters. If we bring beavers back it's just one tool we need to solve Britain's crisis of soil loss and agricultural pollution of waterways, but it's a useful tool," he said.

    Prof Brazier's claims were disputed by the National Farmers' Union (NFU), which warned that the reintroduction of beavers to Scotland had led to fields and forests becoming damaged. Spokesman Mark Pope said: "The knowledge of the impacts beavers have had on farmland, riverbanks and flood defences in Scotland is concerning. We await the results of the Devon trial and will analyse the outcomes then."

    Prof Brazier, an expert in Earth Surface Processes, insisted the animals could even play a useful role in preventing flooding. He told BBC News: "The public is currently paying people to build leaky dams to keep storm waters in the uplands. The beavers can do it free of charge and even build their own homes."

    However, Professor Jane Rickson, a soil specialist from Cranfield University, Bedfordshire, joined the NFU in sounding a note of caution. She agreed that in some places in the UK there was evidence of worrying soil loss, and said new policies were urgently needed. Beavers may in fact reduce the river channel and remove vegetation, exposing banks to greater erosion (侵蚀) and increasing, rather than decreasing, the risk of flooding, she warned. And she said beaver dams should be "leaky" to avoid build-ups of large volumes of water.

    Each year there is an increasing number of cars on roads and streets as millions of new cars and trucks are produced. One out of every six Americans works at putting together the parts of cars, driving trucks, building roads or filling cars and trucks with gas. Americans won't live without cars!

    Most Americans would find it hard to think what life would look like without cars. However, some have realized the serious problems of the air pollution that is caused by the car.

    The polluted air becomes poisonous and dangerous to health.

    One way to get rid of the polluted air is to build a car that does not pollute. That's what several of the large car factories have been trying to do. But to build a clean car is easier said than done. Progress in this field has been slow.

    Another way is to take the place of the car engine by something else. Inventors are now working on steam cars as well as electric cars. Many makers believe that it will take years to develop a practical model that pleases man.

    To prevent the world from being polluted by cars, we'll have to make some changes in the way many of us live. Americans, for example, have to cut down on the number of their total cars. They are encouraged to travel and go to work by bicycle. Bicycling is thought to help keep the air clean.

    But this change does not come easily. A large number of workers may find themselves without jobs if a car factory closes down. Thus the problem of air pollution would become less important than that of unemployment.

    Although cars have led us to a better life, they have also brought us new problems.

    On average, primary school children in England have at least three sugary snacks a day, Public Health England (PHE) found. This means that the sugar they consume is three times more than the recommended maximum.

    Children between the ages of 4 and 10 consume 51.2% of sugar from unhealthy snacks. PHE has launched a campaign, Change4Life, to encourage parents to look for healthier snacks of no more than 100 calories, and to limit them to two a day. The campaign advises parents to give their children a maximum of two snacks a day, with each containing no more than 100 calories. The campaign will also offer parents special suggestions on a range of healthier snacks—ones with 100 calories or fewer—at selected supermarkets, PHE said.

    PHE said it had also improved its app so that it could mark the content of sugar, salt and fat in food and drinks. Dr Alison Tedstone told the BBC she hoped the campaign would help parents to choose healthier snacks for their children. “If you wander through a supermarket, you can see much more goods being sold as snacks than ever before,” she said, “It's a common phenomenon that kids' lunchboxes are full of snacks, leading to a lot of calories for lunch. Our research shows that parents usually appreciate a rule of thumb (经验法则). However, they are surprised to know how much sugar their children are consuming in snacks now.”

    Justine Roberts, founder of Mumsnet, said, “The intake (摄入量) of sugar that kids are getting from snacks and sugary drinks alone is pretty astonishing, and it can often be difficult to distinguish which snacks are healthy and which are not. The rule of thumb from Change4Life can help parents make their decision correctly and wisely. ”

    It's 2035. You have a job, a family and you're about 40 years old. Welcome to our future life.

    Getting ready for work, you pause in front of the mirror. “Turn red,” you say. Your shirt changes from sky blue to deep red. Tiny preprogrammed electronics (智能电子元件) are rearranged in your shirt to change its color. Looking into the mirror, you find it hard to believe you're 40. You look much younger. With amazing advances in medicine, people in your generation may live to be 150 years old. You're not even middle aged!

    As you go into the kitchen and prepare to pour your breakfast cereal（谷物） into a bowl, you hear, “To lose weight, you shouldn't eat that,” from your shoes. They read the tiny electronic code on the cereal box to find out the nutrition details. You decide to listen to your shoes. “Kitchen, what can I have for breakfast?” A list of possible foods appears on the counter as the kitchen cheeks its food supplies.

“Ready for your trip to space,” you ask your son and daughter. In 2005 only specially-trained astronauts went into space—and very few of them. Today anyone can go to space for daytrips or longer vacations. Your best friend even works in space. Handing your children three strawberries each, you add, “The doctor said you need these for space travel.” Thanks to medical advances, vaccination shots (防疫针) are a thing of the past. Ordinary foods contain specific vaccines(疫苗). With the strawberries in their mouths, the kids head for the front door.

    It's time for you to go to work. Your car checks your fingerprints and unlocks the doors. “My office, autopilot,” you command. Your car drives itself down the road and move smoothly into traffic on the highway. You sit back and unroll your e-newspaper. The latest news downloads and fills the viewer. Looking through the pages, you watch the news as video film rather than read it.