You're rushing to work and a man ahead of you collapses (跌倒) on the sidewalk. Do you stop to help? In a study of by-standers, it was found that some people avert their gaze and keep on walking rather than stop and get involved. “There is a tendency to decide that no action is needed.” says a psychologist. “The first thoughts that pop into (进入) your mind often keep you from offering help. In order to take action, you have to work against them.” Here are some common thoughts that might prevent you from helping.

    Why should I be the one? I'm probably not the most competent (有能力的) person in this crowd. You might think someone older or with more medical knowledge should offer assistance (帮助).

    What if he doesn't really need my help? The fear of embarrassment is powerful; no one wants to risk looking foolish in front of others.

    No one else looks concerned-this must not be a problem. We can follow the people around us, but most  people tend to hold back their emotions in public.

     “If you spot (发现) trouble and find yourself explaining inaction, force yourself to stop and evaluate the situation instead of walking on,” says the psychologist. “Then retry to involve other people; you don't have to take on the entire responsibility of being helpful. Sometimes it's just a matter of turning to the person next to you and saying, “It looks like we should do something.” Or asking someone if an ambulance has been called and, if not, to call for one. Once you take action, most people will follow you.”

    Social media is our new travel agent, and it's changing the places we go. In some cases, the places we go. In some cases, the newfound fame brought about by social media platforms has helped to boost local economies and bring tourists to places they might never have discovered otherwise. In other cases, it's creating problems for countries and cities that are simply not equipped to deal with the influx(涌入) of tourists. Check out two of the incredible locations around the world that have gone viral on social media.

    Iceland

    This northern island nation has seen a dramatic surge(激增) in visitors over the past few years. One reason for that is the so-called "Game of Thrones effect,". This, combined with the availability of cheap flights and some very effective marketing campaigns, has made Iceland a popular travel destination. The number of tourists almost doubled from 566,000 to over 1 million between 2011 and 2015, according to Iceland's tourism board.

    While this influx of visitors has brought a much-needed boost to the economy post-recession(经济衰退), it's also pushed up prices for residents and put pressure on the infrastructure. Locals complain of tourists destroying the fragile ecosystem and leaving a mess behind them as they trample over the formerly untouched natural sites.

    Cuba

    According to Cuba's ministry of tourism, four million visitors went to Cuba in 2016, an increase of 13 percent from the year before. The tourism boom has had some consequences for the country's residents, The New York Times reported in December 2016.

    The surge in visitors has led to a food shortage, and basic food items have become completely unaffordable for locals. Local hotels and restaurants are buying up supplies in bulk for guests, pushing up prices and leaving limited amounts for locals.

    The situation has been acknowledged by the Cuban government, who put caps on prices to make them more affordable for residents. This has only encouraged sellers to put products on the black market, according to The New York Times.

    A famous study was done in a school by a professor from a university. At the start of the school year, the teachers were given the names of five children. They were told that these five were the most excellent students in the class. But the fact was that these students were only average, and they were not the best students at all. Well, guess what? At the end of the year, all the five average students scored among the highest in the class.

    What made these average students change so much to become top students? The only difference was the change in their teachers' attitude. Because the teachers believed that these five kids were the top students, they expected (期望) more from them. And so these five average students began to believe and expect more from themselves. So they worked harder to do as well as they could.

    Do you know why? If you expect the best from people, they'll usually want to give you their best. A great leader said, “Treat (对待) a person just how he appears to be on the outside, and you'll make him even worse. But treat a person like he's already a success, and you'll help make him the best he can be.”

    Like the true story of 7-year-old Johnny, his teacher got so angry with him that one day she said, “Johnny, you're the naughtiest (最顽皮的) boy in this class. I'm sure you'll never change.” The next year Johnny had a new teacher. And on the first day of class, she met with Johnny after school and said, “Johnny, I've heard a lot about you! But do you know that I don't believe a word of it.” And every day after that, this new teacher treated Johnny as if he was one of the smartest students even when Johnny did naughty things. Later on, Johnny became a school leader. Because that's the power of our belief and attitude toward children.

    What makes a building ugly? Everyone's got their own opinion, so it's hard to say. Now, let's take a look at some of the world's worst buildings.

    The Torre Velasca

    The Tone Velasca in Milan is in the centre of Milan (Italy). The tower, which went up in the 1950s, is about 100 metres tall. Its design is actually a modern representation of a traditional Lombard castle, where the lower parts were narrower (狭窄的）than the upper parts.

    The Mirador Building

    The Mirador Building in Madrid (Spain) was created by Dutch studio MVRDV and the Spanish architect Blanca Lleo. The building, which is a block of flats, opened in 2005. There is a large rectangular (矩形的）hole in the upper part of it, which is used by the neighbourhood as a meeting area and playground.

    The Prague TV Tower

    The Prague TV Tower is in Prague (the capital of the Czech Republic). It stands 216 metres high and looks a bit like a tall, thin space ship. Prague is famous for its architectural beauty,so when the tower was put up in 1985 by architect Vaclav Aulicky and engineer Jiri Kozak, many felt it didn't fit in.

    The Longaberger Basket Company

    The Longaberger Basket Company building is in Newark, Ohio (USA). The office block was opened in 1997 and looks like a very large basket. It，s got seven floors and two handles at the top. The handles weigh about 150 tons. It may not be the ugliest building in the world but it's certainly one of the most unusual.

Life in the Clear

    Transparent animals let light pass through their bodies the same way light passes through a window. These animals typically live between the surface of the ocean and a depth of about 3,300 feet — as far as most light can reach. Most of them are extremely delicate and can be damaged by a simple touch. Sonke Johnsen, a scientist in biology, says, "These animals live through their life alone. They never touch anything unless they're eating it, or unless something is eating them."

    And they are as clear as glass. How does an animal become see­through? It's trickier than you might think.

    The objects around you are visible because they interact with light.  Light typically travels in a straight line. But some materials slow and scatter (散射) light, bouncing it away from its original path. Others absorb light, stopping it dead in its tracks.  Both scattering and absorption make an object look different from other objects around it, so you can see it easily.

    But a transparent object doesn't absorb or scatter light, at least not very much. Light can pass through it without bending or stopping. That means a transparent object doesn't look very different from the surrounding air or water. You don't see it — you see the things behind it.

    To become transparent, an animal needs to keep its body from absorbing or scattering light. Living materials can stop light because they contain pigments (色素) that absorb specific colors of light. But a transparent animal doesn't have pigments, so its tissues won't absorb light. According to Johnsen, avoiding absorption is actually easy. The real challenge is preventing light from scattering.

    Animals are built of many different materials — skin, fat, and more — and light moves through each at a different speed. Every time light moves into a material with a new speed, it bends and scatters. Transparent animals use different tricks to fight scattering. Some animals are simply very small or extremely flat.  Without much tissue to scatter light, it is easier to be see­through. Others build a large, clear mass of non­living jelly­lie (果冻状的) material and spread themselves over it.

    Larger transparent animals have the biggest challenge, because they have to make all the different tissues in their bodies slow down light exactly as much as water does. They need to look uniform. But how they're doing it is still unknown. One thing is clear for these larger animals, staying transparent is an active process.  When they die, they turn a non­transparent milky white.