1 . When we want to communicate with another person, we generally use our voice, such as speaking or shouting. They are great ways to communicate, but they have some drawbacks.

For instance, if you live on a mountainside and your friend lives on another mountainside, shouting to each other isn’t always that effective. Shouting creates lots of echoes (回声) among the corners and holes of mountains, and the average outdoor range of an understandable human voice is only about 180 meters. Unless you walk over to where your friend lives to carry on a conversation at a reasonable speaking distance, or communicate by some sort of visual technique like smoke signals, there’s not much to be done except whistle (吹口哨).

Whistling is the product of air being forced through a small hole made by your lips. A whistle is different from your voice because it’s clear, and the frequency is high. The sound of a whistle can carry for over 8 kilometers and it holds its form, while a shout can become a mess because of the echoes.

For thousands of years, humans have relied on spoken language to accomplish daily, face-to-face communication most of the time. And in recent years, the coming of text messaging has also made whistled languages take a dive worldwide. Luckily, there are still over 70 groups around the world that engage in special whistled languages.

They’re most commonly found in mountainous regions where farmers need to pass messages around without walking up and down hills, and whistles are also used to communicate through the thick Amazon rainforest and are useful to Inuit at sea as well. Hunters can use whistling to communicate with each other in a way that doesn’t alarm their targets as the voice-produced language might.

Whistled languages are unique to a certain area and they are not distinct from spoken language. However, whistled language speakers around the world are found to be able to understand about 90 percent of what’s communicated. When whistled languages are still present, it signals that traditional activities are still commonly practiced and therefore the cultures behind them have been maintained.

3 . Someday, you may no longer need to brush your teeth by hand. Instead, billions of nanoparticles(纳米颗粒)could automatically do all that work for you. The nanoparticles are very tiny. Magnets(磁铁)can make them move. If you set up a magnet in just the right way, says Ed Steager, “You can arrange them into any shape you want.”

Steager is an engineer at the University of Pennsylvania. Together, he and his colleague Hyun Koo found a way to form the nanoparticles into long, skinny bristles(鬃毛), a lot like the ones on a toothbrush. But these bristles shape-shift to fit whatever surface they encounter. They can even squeeze between teeth.

The scientists tested the robotic bristles in the lab. But the device isn’t yet ready for people to use. The magnets and nanoparticles will need to fit comfortably and safely inside a person’s mouth. The researchers are working with a company to accomplish this safely and effectively. But if these inventors can perfect the device, a lot of people will benefit, especially the disabled.

The tooth-cleaning robot works thanks to two magnets. One goes on each side of the teeth. The nanoparticles sit in a water-based solution between the magnets. All of this may fit into something the size and shape of a mouthguard, though the researchers haven’t settled on a design for the device yet.

As a bonus, the nanoparticles also kill those harmful bacteria in the mouth. The water-based liquid that holds them contains a substance commonly added to toothpaste(牙膏)and mouthwash. It kills some bacteria on its own. But when these nanoparticles react with it, powerful germ-killing substances get created.

The new device is just a proof of a notion. The researchers still need to turn it into a product that people will want to use. It must fit comfortably and safely in people’s mouths. It can’t draw too much power or cost too much. “There’s a lot of engineering to get from here to there,” says Steager. But, as Melo says, “every good idea needs to have a start.”

4 . The Negative Impacts of Volunteer Tourism

Volunteer tourism, or voluntourism, is an increasingly popular form of altruistic travel. Its appeal lies in being an experience that allows visitors to feel good by being a part of some kind of meaningful change. But despite good intentions from participants, volunteering abroad has been the target of heavy criticism over the past few years.

Voluntourists only have a limited amount of time, and the ability to change the systems and provide support for the places they visit. Being volunteers, they also simply don’t have the skills to do so. And they can sometimes inadvertently perpetuate unhelpful and even patronizing(自视高人一等的)ideas about the places they visit. A number of studies have shown that volunteer tourism can have negative impacts, ___________benefiting the local communities.

*Unskilled labor creates more work

Previously, volunteering opportunities were often___________to skilled professionals, but this is not the___________of volunteer tourism. Anyone can become a voluntourist, which brings a series of problems. Though___________, they are often unskilled, especially when it comes to work such as construction and digging. This can often lead to locals being forced to take on the added responsibility for rebuilding homes and schools that would have been___________inadequate.

*Volunteers take local jobs

In the meantime, this takes jobs away from locals who would have been paid to do the same work. It also prevents them from learning or being taught the skills that could then be used to___________the community. As a famous proverb says, “Give a man a fish, and you feed him for a day. Teach him how to fish, and you feed him for a lifetime.” The time and efforts of volunteers could be better___________making local communities more economically independent and self-sufficient, allowing them to improve___________even after they depart.

*There is no long-term commitment

Lots of communities do need the help and assistance of volunteers, but what are they able to address in the few short weeks of their “___________”? Most places tend to benefit more from long-term engagement, and often the largest number of meaningful volunteers come from the communities themselves, rather than from____________eager to fix things. While short-term volunteers can do a lot of good, it is often so only when they have skills and training that____________the specific needs, such as medical aid, construction, conservation, teaching, or even religious work; as well as having experience doing the required work and with different cultures.

* There is a lot of focus on__________the volunteer

Voluntourism tends to place a lot of emphasis on the volunteers, sometimes even at the expense of the community they are looking to help. Travel companies attract individuals with promises of____________but immediately-rewarding experiences. This, in turn, can lead to large numbers of volunteers who, instead of helping create a change, can actually____________local communities from becoming more economically independent due to their very presence.

What Can We Do Instead?

Short-term volunteers, especially students, also need to be given the opportunity to explore various different cultures and destinations. But they should take the time to learn about the socio-cultural backgrounds of the places they visit. Short-term placements thus become more about experiences and____________exchange, where they may gain knowledge and respect other cultures, rather than go on trips that “help the poor”.

This kind of cross-cultural engagement can do a lot of good in a world that is increasingly leaning towards violence and xenophobia.

6 . In the city of Lyon, hundreds of the world’s finest chefs gathered on 26 January for the funeral of Paul Bocuse, the man credited with the creation of innovative cuisine (菜肴). Meanwhile, in branches of the Intermarche supermarket across France, shoppers were _________to get hold of one-kilogram jars of Nutella, on special offer at just €1.41, down from about €4.50. One branch shifted 400 jars in 21 minutes. Videos showed shoppers stuffing jars of Nutella into bags. Some customers came the night before the promotion to _________the Nutella pots in other places in order to prevent them from being taken. Shoppers broke items in their _________ for the treat.

Thus, a dirty secret is uncovered: France has fallen in love with cheap, fast food. It’s tempting to think that perhaps France should _________its bright self-image along with the master.

McDonald’s, the leader of all things unpalatable (令人讨厌的) yet delicious, opened its first branch in France in 1972, but it operated so badly that the company _________from the country soon. In 1979, McDonald’s returned and succeeded by going _________, which extended far beyond renaming its food. It _________identified the French preference for eating at table or in family and made sure the environment of its outlets was the same to comfort as to speed. Since then, France has grown to become McDonald’s most profitable market outside the US, with more than 1, 400 branches at the end of 2016. Burger King, _________, came in waving stars and stripes high and left with its tail between its legs in 1997 though it returned in 2012 with a far more _________strategy. None of this has gone exactly unnoticed, especially when fast food __________traditional restaurants in 2012, leaving traditionalists angrily waving their ham-and-butter baguettes (法式长棍面包) at the newcomers.

Nutella has had a(n) __________ride in France. Developed in post-war Italy at a time of cocoa rationing (定量配给) and hazelnut glut (榛子过剩), the Ferrero company’s spread was an instant __________when introduced in France in the 1960s. Half of all French families have it on their breakfast table, and for adults it has come to represent a taste of childhood. Such is the __________that one French couple were prevented from naming their daughter Nutella only by legal act.

If there is a(n) __________in Nutella, it is its ingredient, whose production has been linked to deforestation and the destruction of natural habitats, pushing the French government to impose a special “Nutella” tax on products from palm oil. France’s Super U supermarket chain, a rival to Intermarche, has already __________palm oil from its own-label products, and the pressure on the big brands to do the same is likely to increase.

7 . Self—acceptance leads to happiness

Finding acceptance is a natural desire of most people. When we are young, it is important to us to be_________by a group and to be seen as “cool” by our peers. To do this, we will often adopt the views and interests of the group_________develop our own.

Over time, _________, we have the opportunity to learn to accept ourselves. People who have done this are confident in their true abilities; they do not feel the need to create a facade(虚假的外表) to_________other people. They are concerned with whether their actions produce_________results rather than with how they are seen by others.

Less secure people are quite different. Instead of finding security in themselves, they look for other people to provide it. This kind of person_________agrees with everything others suggest, for fear of having their own ideas_________. Arrogant or defensive people are also usually insecure; in an attempt to hide their_________, they belittle or blame others.

Secure people do not_________when faced with a difficult situation; they say “I can” rather than “I can’t”. Knowing that each day is an opportunity to use their talents to acquire good health, good friendships, and great happiness, they always put their best foot forward. __________people do not judge others, nor do they judge themselves. They can__________ the differences between themselves and other people.

Recognizing the details that we cannot change about ourselves is also a sign of personal__________. We cannot change our height, so why waste energy complaining about being__________? Our energy would be better spent on more constructive projects. Instead of__________personal characteristics we are not satisfied with, we ought to focus more on what we are good at.

Such expressions as “love thyself” and “to thine own self be true” are about self-acceptance and confidence, as well as honesty and morality. We should consider them to be good advice, and treat them as__________showing the way to happiness within.

8 . Born in 1926, Princess Elizabeth Alexandra Mary was not originally chosen for the special position. However, that changed in 1936, when her father’s brother Edward Ⅷ gave up being the king and her father, George Ⅵ, took his place as the king. Suddenly, the 10-year-old was the heiress(女继承人).

Elizabeth’s royal(王室的)duties didn’t stop her interest in technology. During World War II, the princess wanted her father to allow her to do something for her country. Her father finally agreed to let her volunteer for the British Army, where she became a driver and trained in auto mechanics.

It was a pioneering move: Not only was she the first member of her family ever to serve in the military, but the sight of a woman taking apart engines and changing tires signalled a sea change in social and gender roles that would continue throughout the future queen’s lifetime.

In 1952, Elizabeth became queen of her country upon her father’s death. Her rule was modern from the very start. The new queen’s birth had roughly happened at the same time as the development of television, and during planning for her coronation(加冕礼)she broke with tradition and allowed the BBC to broadcast the event over live TV. It was the first coronation ever televised, and it literally created must-see TV.

Elizabeth came to power as the atomic age kicked into full swing, and she helped introduce the nation to those nuclear advances. In 1956, she opened the world’s first complete nuclear power station, Calder Hall. But the technology came with risk: The next year, a reactor at a nearby nuclear power plant, Windscale, caught fire, which was Great Britain’s worst nuclear disaster.

The queen also launched live broadcasts of royal addresses and permitted royal use of the Internet. Besides, she was one of the first people to ride through the Channel Tunnel, the undersea railway linking Britain to the rest of Europe.