I had been following the yellowish-green markers for a “popular and easy” three-mile out-and-back hike. Immediately after the trailhead(山道的起点), the trail became very rocky and steep. But having read information about the hike, I knew within five minutes, I was supposed to reach the hike's first overlook.

    However, the overlook never arrived. Instead, I found myself lost in the woods. Pulling out my cellphone, I saw it read “no service”. I checked the last text message I'd sent to my mom. It read, “Conference ended…going for a small hike before my flight home this afternoon.” I put my phone away and kept moving and yelling, “Help! Is anybody out there?” Every so often, I'd stop to listen, but I never heard a reply.

    I got out my phone again. The battery was running out fast as it searched for a signal. I struggled to find a place where I could get service. When I did, I called my mom. It went through! In a shaky voice, I said, “Mom?” And then the call dropped. More than 1,500 miles away, my mom instantly knew something was wrong. She called the Denver Police Department and was directed to the US Forest Service.

    This was how I was introduced to John, an operator from the US Forest Service. Following John's instruction on the phone, I finally escaped from the woods. I breathed a sigh of relief. Then my phone rang, and it was John, making sure I was still going in the right direction. “By the way,” he said, “we've had your mother on hold this whole time. We know once you get down the mountain, you will absolutely want to give her a call.”

    In February, 2015, a South Korean woman was sleeping on the floor when her robot vacuum ate her hair, forcing her to call for emergency help. It surely isn't what Stephen Hawking warned us that intelligent devices “mean the end of the human race”. But it does highlight one of the unexpected dangers of inviting robots into our home.

    There are many examples of intelligent technology going bad, but more often than not, they involve cheating rather than physical danger. Meanwhile, increasing evidence suggests that we, especially children, tend to tell our deepest, darkest secrets to human robots. So how do we protect ourselves from giving-away code?

    Once you've invited a robot into your home, you need to manage your expectations. Movies and marketing may have told us to expect deep interaction with robots friends but we've still got a long way to go before they are as socially aware as described. Given the gulf between expectation and reality, it's important to avoid being tricked.

    The message is clear: as robots became increasingly connected to the internet, and able to respond to natural language, you need to especially cautious about figuring out who or what you are talking about.

    We also need to think about how information is being stored and shared when it comes to robots that can record our every move. Some recording devices may have been designed for entertainment but can easily be adapted for more dangerous purposes. Take Nixie, the wearable camera that can fly off your wrist at a moment's notice and take shots around you in the air. It doesn't take much imagination to see how such technology could be taken advantage of.

    If the technology around us is able to record and process speech, images and movement, or listen secretly to us, what will happen to that information? Where will it be stored? Who will have access?

    So, what is the safest way to welcome robots into our homes, public spaces, and social lives? We should be cautiously optimistic that intelligent machines could become enriching companions, while acknowledging that we need to determine strict boundaries for robots. There should be someone to turn to should your robot commit a crime, steal your card... or try to eat your hair.

    When you are travelling, whether on business or for pleasure, you often need to stay in a hotel. The kind of hotel you choose probably is decided above all according to how much money you want to spend. There are small hotels with very few services, where the prices are low, or there are large hotels with all the very latest comforts, where you could spend all the money you have in the bank for one very comfortable night.

    There are several different kinds of people who go to hotels. Some want to live, rather than just stay, in a hotel; the hotels which are designed to meet their needs are called residential hotels. However, most people who stay in hotels are either business people or tourists on holiday.

    In most hotels, there are two kinds of rooms: single rooms, for the use of one person, and double rooms, for the use of two people. In addition, in large hotels, there are also suites(套房), which include two or more rooms connected together—perhaps a bed-room and a living room. They are for people who are very rich or very important.

    Are you sometimes a little tired and sleepy in the early afternoon? Many people feel this way after lunch. They may think that eating lunch is the cause of the sleepiness. Or, in summer, they may think it is the heat. However, the real reason lies inside their bodies. At that time—about eight hours after you wake up—your body temperature goes down. This is what makes you slowdown and feel sleepy. Scientists have tested sleep habits in experiments where there was no night or day. The people in these experiments almost always followed a similar sleeping pattern. They slept for one long period and then for one short period about eight hours later.

    In many parts of the world, people take naps in the middle of the day. This is especially true in warmer climates, where the heat makes work difficult in the early afternoon. Researchers are now saying that naps are good for everyone in any climate. A daily nap gives one a more rested body and mind and therefore is good for health in general. In countries where naps are traditional, people often suffer less from problems such as heart disease. Many working people, unfortunately, have no time to take naps. Though doctors may advise taking naps, employers do not allow it! If you do have the chance, however, here are a few tips about making the most of your nap. Remember that the best time to take a nap is about eight hours after you get up. A short sleep too late in the day may only make you feel more tired and sleepy afterward. This can also happen if you sleep for too long. If you do not have enough time, try a short nap—even ten minutes of sleep can be helpful.

    Some people believe that international sport creates goodwill between the nations and that if countries play games together they will learn to live together. Others say that the opposite is true: that international contests encourage false national pride and lead to misunderstanding and hatred. There is probably some truth in both arguments, but in recent years the Olympic Games have done little to support the view that sports encourage international brotherhood. Not only was there the incident of tragedy involving murder of athletes, but the Games were also ruined by lesser incidents caused principally by minor national contests.

    One country received its second-place medals with visible anger after the hockey final. There had been noisy scenes at the end of the hockey match, the losers objecting to the final decisions. They were convinced that one of their goals should not have been disallowed and that their opponents' victory was unfair. Their manager was in a rage when he said; "This isn't hockey. Hockey and the International Hockey Federation are finished." The president of the Federation said later that such behavior could result in the suspension of the team for at least three years.

    The American basketball team announced that they would not yield first place to Russia, after a disputable end to their contest. The game had ended in disorder. It was thought at first that the United States had won by a single point, but it was announced that there were three seconds still to play. A Russian player then threw the ball from one end of the court to the other, and another player popped it into the basket. It was the first time the US had ever lost an Olympic basketball match. An appeal jury（评审委员会）debated the matter for four and a half hours before announcing that the result would stand. The American players then voted not to receive the silver medals.

    Incidents of this kind will continue as long as sport is played competitively rather than for the love of the game. The suggestion that athletes should compete as individuals or in non-national teams, might be too much to hope for. But in present organization of Olympics there is far too much that encourages aggressive patriotism（爱国主义）.

I was asked by a reader recently why so many animals seem to have pink ears，when their bodies are all different colours? The truth is that most animals actually don't have pink ears. Let us explain.

Near the equator (赤道), where the climate is hot, animals are likely to have darker skin, including on their ears. Think of the African elephant, which has quite dark ears. In colder climates, skin colour is usually lighter and often pink.

Why is skin colour different in different climates? Skin pigmentation, which is what gives skin its colour, can protect against sunburn and skin cancer. When animals live in colder parts of the world, they don't need it as much to survive. Light-coloured skin also helps animals stay warmer because it reduces heat loss, which is useful if you're in a colder climate.

For most animals, the colour of their fur or other body covering has generally developed as camouflage. That allows animals to mix into the background and avoid being eaten, or for predators (捕食者) to remain hidden during hunting. One example is the sandy-coloured coat of the desert fennec fox, which uses camouflage for both hunting and hiding.

By the way, in many animals, ears come in many different shapes and sizes. For example, in bats, the serval (a type of African wildcat) and the fennec fox, the ears are large compared to their body size—this helps them hear better because it allows them to sense more sound waves. Naked mole-rats have tiny ears because they need to dig a lot. Big ears would get in the way. The other downside of big ears is that you can lose a lot of body heat. That's why animals that live in really cold places, like the Arctic fox, have quite small ears.