【推荐1】Many dentists are worried about their patients consuming too many sugar-filled sodas, sweet drinks and non-nutritious snacks. These foods don't have much nutritional value and they can take a toll on teeth.

What affect how quickly youngsters may develop tooth decay(蛀牙)are the eating habits and their food choices.With bacteria coming into contact with sugar in the mouth, acid( 酸)is produced. It will attack the teeth and eventually lead to tooth decay.

Foods containing sugar of any kind can lead to tooth decay. Almost all foods, even milk and vegetables, contain some type of sugar. Some of them, however, are a necessary part of a healthy diet due to their nutritional value. To help control the amount of sugar you consume, you need to read food labels carefully and choose foods and drinks with lower added sugar. Drinks, sweets and biscuits that contain a lot of added sugar shouldn't be on your shopping list.

Maintaining a diet lacking certain nutrients may increase the risk of tissue(4#A )infection in your mouth, which may result in a major cause of tooth loss in adults-the periodontal disease(2 a%P). Although poor nutrition and the periodontal disease are not directly related, many studies show that the disease progresses faster and can be more severe in people with nutrient-poor diets.

To make sure of enough nutrition, we need to maintain a balanced diet. Eating a variety of foods from each of the five major food groups and consuming less snacks will help a lot. If you do snack, choose nutritious foods, such as cheese, raw vegetables, plain yoghurt, or a piece of fruit.

【推荐3】Are you content with the shape of your nose? If not, the climate may be to blame, not your parents.

This is according to a recent study carried out by scientists from Pennsylvania State University, US. They found that climate played a key role in shaping our noses. The findings were based on an examination of the size and shape of noses of 476 people from four regions — West Africa, East Asia, South Asia and Northern Europe, using 3D facial imaging technology.

“People have thought for a long time the difference in nose shape among humans across the world may have arisen as a result of natural selection because of climate,” Arslan Zaidi, one of the lead authors of the study, told the Guardian. But while previous studies were based on measurements from human skulls(头骨), Zaidi and his team looked at nose shape itself.

The result showed that wider noses are more common in warm and humid climates, while narrower noses are more common in cold and dry climates. That, Zaidi said, could be because narrower nasal passages (鼻道) help to increase the wet content of air and warm it, which is easier on our lungs. This, in turn, led to a gradual decrease in nose width in populations living far away from the equator (赤道).

More study is still needed to test the link between climate and nose shape, but Zaidi believes the current findings are valuable in understanding potential health issue. “As we become more of a global community, we are going to come across climates that we are not adapted to,” he told the Guardian. This means moving to a very different climate might increase the risk of breathing problems.

However, he added, “This may not be necessarily true for various reasons such as of modern medicine and the fact that our current climate is very different from what it used to be.”

【推荐1】The first traffic lights in the United States were installed (安装) because of an increase in traveller on the road in the 1920s. Worried about accidents, towns and cities built traffic towers to help the flow of cars. Officers manned the towers, using whistles and red, green and yellow lights to indicate to drivers when they should stop and go.

Due to the absence of effective traffic signal systems on some streets, it caused risks at corssroads. Then, William Potts created the first tricolour, four-directional traffic signal. The very first four-directional traffic light was installed at Woodward Avenue and Fort. But throughout the country, there were still a lot of systems for traffic lights and patterns in place. Since this could end up causing more problems for drivers, the Federal Highway Administration set uniform standards in 1935 for all road signs, pavement markings and traffic signals, requiring them to all use red, yellow and green light indicators.

Red is the colour with the longest wavelength, which means that as it travels through air molecules, it gets diffused (扩散) less than other colour, so it can be seen from a greater distance. Yellow has a shorter wavelength than red but a longer wavelength than green. This means that red is visible the furthest away, yellow in the middle and green the least distance away — a helpful advanced warning for needing to slow or stop. But this could be a coincidence. Red meaning stop originated with train warning lights, and it’s not clear whether that was chosen based on wavelength, contrast against green nature or natural association of red with things like blood. It could be a combination of all three!

Back in the 1900s, some stop signs were yellow because it was too hard to see a red sign in a poorly lit area. Eventually, highly reflective materials were developed, and red stop signs were born. Since yellow can be seen well at all times of the day, school zones, some traffic signs and school buses continue to be painted the colour.

【推荐2】Robots are not new.     1    . Any modern manufacturing or processing plant or factory uses robots in some way or ways. Manufacturers know that to stay competitive, you need to cut costs and improve efficiency in your production line. Robots are the perfect solution.

We have used robots in the home environment for some time too.       2     They are programmed to clean the floors. But now in 2018, Moley, a London based robotics company has brought all the technology and engineering brilliance of robots into one package to produce the world’s first fully-automated and intelligent cooking robot. The consumer version set will be launched in 2020. Moley is turning the dream of unlimited access to chefs and their recipes worldwide into reality.       3     It can even cook your own recipes and share them with others all in your own home.

It’s already been tested in the Robotics Show in Hannover Messe.       4     The three major talking points are as follows.

•It works really well.

•It looks fantastic.

•It links up with other state of the art ideas.

An example of the third point is that iTunes has a wealth of recipes available.     5    

【推荐3】Offshore wind turbines (风力发电机) could generate enough electricity to power every home and business on Earth, according to a new report published by the International Energy Agency (IEA). The IEA describes the results as the "most comprehensive global study" of offshore wind.

Fatih Birol, executive director of the IEA, said that offshore wind has the potential to join oil, gas and solar power as energy sources that have enjoyed a boom in production following a sharp fall in costs. "Offshore wind currently provides just 0.3% of global power generation, but its potential is vast," Birol said. "More and more of that potential is coming within reach, but much work remains to be done by governments and industry for it to become a mainstay." Increased government support and new investment would help unlock new technology, including floating platforms that would allow turbines to be located much further out to sea.

The report says that developing well-equipped wind sites located close to shore would supply more than the total amount of electricity consumed worldwide today. The maximum potential for offshore wind production is more than 120,000 gigawatts (千兆瓦) , or 11 times projected global electricity demand in 2040, although that estimate does not factor in difficulties in transmitting and storing the power generated.

Wind power will be able to satisfy increasing demand for clean power to reduce the carbon use, according to the IEA. In the European Union, for example, offshore wind capacity is set to be the region's largest source of electricity in the 2040s. Its growth is expected to far outpace the increase in electricity demand, allowing surplus wind power to be used to produce hydrogen (氢) , which in turn could reduce carbon use in transportation and building.

Chinese government policies designed to meet sustainable energy goals will help the country overtake the United Kingdom as having the largest offshore wind fleet by 2025. The push will see China's offshore wind capacity rise from 4 gigawatts in 2019 to 110 gigawatts by 2040. Other countries with a large number of coastal urban centers are also set to benefit, said the IEA.

【推荐1】True real friends double your happiness and half your burdens. Basically how you would like a true real friend to be, you should be like this to your true friends. Trust, forgiveness, accountability（责任）are some ingredients of a true friend. True friendships are hard to come by. And what’s more, life is short. So treasure these friends if you have already had them. If you don’t continue to search, because once you have them, life becomes so much easier to live, no matter what happens. I have been through pretty rough patches and I dare say, without my friends I would not have made it.

Friendships need lots of energy and patience to maintain them. Not to mention time too. When your friend needs you, sometimes when things are not going too well on your side, it is often so easy to turn a deaf ear to their pleas（请求）. It is especially during these times, that you must find the strength in you to help your friend. And it is during these times that your friendship will be forged and made stronger.

And you must always be happy for their successes, even when things are not going too well on your side. It might be hard to do for some people, but it is something that you need to learn. Think about all the sacrifices your friend has made for you and all the times when he or she was happy for you despite his or her own troubles.

Think about all the happy times you all enjoyed and the sad, rough times you all went through together. That should give you sufficient patience to actually be a true friend for them. Remember, true friends are the next best thing to family. They will always be your pillar of support no matter what. Always.

【推荐3】Capybaras (水豚) are group animals, so they do not like being alone. In fact, leaving a capybara alone is not only uncomfortable for the animal, but it can be harmful to their physical health, as well as their mental happiness. Capybaras love to talk to each other throughout the day. Groups of capybaras spend their days sun bathing along the edge of rivers, where they enjoy swimming together in the water. They spend half of their lives in the water.

Since they spend so much time around water, it makes sense that capybaras would come into contact with different kinds of other animals who stop in for a drink. Capybaras are gentle and peaceful river animals who enjoy a short sleep along the water’s edge — and often do so with other animal species as well. You can find pictures all over the Internet of these lovely animals lying beside turtles, birds, ducks, rats, and even monkeys as they enjoy a nap by the water.

Capybaras are also known to be excellent and friendly taxis in the animal world. Birds and monkeys commonly stand on the back of a capybara for a ride as capybaras search for grass to eat. Sometimes capybaras even serve as boats for other animals, letting them sit on their heads as they swim through the water.

However, if you see a capybara lying on its side with a yellow-headed caracara (长腿秃鹰) on its body, don’t panic just yet. Most likely the copybara is enjoying a nice spa day. Birds often make friends with capybaras and provide a natural cleaning service, picking off insects that live in the capybara’s fur. It’s a relationship that benefits each other, since the yellow-headed caracara also gets to enjoy eating those tasty insects. Yet, such lovely capybaras are not free of human influences and even face extinction now.

【推荐1】The United Nations'World Food Program, WFP, won the Nobel Peace Prize on Friday. The Norwegian Nobel Committee is recognizing the group for its efforts to fight hunger and improve conditions for peace in areas affected by conflict. The award comes with a gold medal and $1.1 million --a small amount compared to the money the WFP needs for its work. So far in 2020, the UN agency has received almost $6.4 billion in goods and other donations.

The World Food Program has long specialized in getting assistance to some of the world's most dangerous places. For example, the WFP has air-dropped food in South Sudan and Syria. It also created an emergency service that kept working as COVID-19 delayed many flights.

In 2019, the UN agency provided aid to almost 100 million people in 88 countries. Berit Reiss-Andersen, chairman of the Norwegian Nobel Committee, said on Friday, “With this year's award, the committee wishes to turn the eyes of the world to the millions of people who suffer from or face the threat of hunger.” In announcing the award, the Nobel committee noted that “Until the day when we have a medical vaccine (疫苗），food is the best vaccine against chaos.” And it added, “there will be 265 million starving people within a year, so of course this is also a call to the international community not to underfund the World Food Program.”

In Geneva, a WFP spokesman told reporters: “When everything went into shutdown mode, the World Food Programme was there. When everyone was leaving, the World Food Programme had to provide the support that the world deserved.”

Dan Smith is director of the Stockholm International Peace Research Institute. He said the Nobel committee had wanted to send a message of both hope and support for international cooperation. “Hunger, like climate change, the pandemic (疫情） and other issues, is a world problem that can only be properly addressed through cooperation,” he told Reuters news agency.

【推荐2】Four apps for students to learn English

Quizlet is a learning app — a computer program you use on your mobile device. It can help users build and test their knowledge of English words and terms. Quizlet has word sets for millions of subjects. And, it is quickly becoming a useful mobile tool for language learners.

In Socrative, teachers can create timed learning games. In class, students compete individually or as part of a team against classmates. One game students love is called space Race. In this game, if a team answers a question correctly, their rocket moves forward. This team whose rocket gets to the end first wins. Also, teachers can use Socrative as an “exit ticket,” a question they can ask students about what they learned in that day’s class. Students write their answers on their mobile devices. Then, the teacher can show the answers on a shared video screen.

A QR Code is a kind of sign that a smartphone can read with its camera. When your phone camera reads a QR code, it takes you to a website, image, video or anything you want to share. For example, one will take you to the VOA Learning English website.

Evernote lets users store and share notes, images and recordings in one place. Teachers can also use Evernote to give homework.