I began as a calculating machine in 1642 in France. In 1822 I was built as an analytical machine. Then in 1936 Alan Turing wrote a book and built a universal machine. As the years have gone by, I have been made smaller. There were times when my size totally changed. And my memory became so large that I couldn't believe it. In the 1960s they gave me a family connected by a network. I was able to share my knowledge with others through the World Wide Web. Since the 1970s many new applications have been found for me.

    Now many young people are traveling around the world on their own，not because they have no one to travel with，but because they prefer to go alone.

    Kristina Wegscheider from California first traveled alone when she was at college and believes that it is something everyone should do at least once in their life. ＂It opens up your mind to new things and pushes you out of your comfort zone.＂ Wegscheider has visited 46 countries covering all seven continents.

    In foreign countries，with no one to help you read a map，look after you if you get ill，or lend you money if your wallet is stolen，it is challenging. This is what drives young people to travel alone. It is seen as character building and a chance to prove that they can make it on their own.

    Chris Richardson decided to leave his sales job in Australia to go traveling last year. He set up a website，The Aussie Nomad，to document his adventures. He says he wished he had traveled alone earlier. ＂The people you meet，the places you visit，or the things you do，everything is up to you and it forces you to grow as a person，＂ said the 30-year-old man.

    Richardson describes traveling alone like ＂a shot in the arm＂，which ＂makes you a more confident person that is ready to deal with anything＂. He said，＂The feeling of having overcome something on my own is a major part of what drives me each day when I'm dealing with a difficult task. I walk around with my head up because I know deep down inside that nothing is impossible if you try.＂

    The great 19th century explorer John Muir once said，＂Only by going alone in silence can one truly get into the heart of the wilderness.＂

    “This is your last chance,” warned Mrs Gillfeather. I broke out in a sweat and my hands started to shake. We both wanted to get to sleep, but before we could, I had to put a cannula(针管) in her arm.

    Before becoming a doctor I'd only a vague idea what a cannula was, coming from an hour spent with a plastic arm while at medical school. Once I became a doctor, however, I couldn't seem to get away from them.

    For those of you who are lucky enough to have never come into contact with one, they're tiny little tubes that are put into a vein(静脉)so that fluid or medicines can do directly into the blood. That's the theory. Unfortunately, the problem is that for them to work, you have to get them into the vein in the first place. This tends to be trickier than you'd imagine—and it's a job that tends to fall on the junior doctors.

    Mrs Gillfeather's veins were particularly elusive that evening. I'd been jabbing the needle in for at least 20 minutes.

    “Isn't there someone else who could do this?” she asked, for the fourth time. “Someone who knows what they're doing, perhaps,” she said under her breath, just loud enough for me to hear.

    Finally, I got it in. Mrs. Gillfeather and I both breathed a sigh of relief

    Just as I was about to leave the ward, the nurse called me over, “Max, there's another cannula to do on bed 16.”

    First aid is emergency care for a victim of sudden illness or injury until more skillful medical treatment is available. It may save a life or improve certain vital signs including pulse, temperature，a clear airway(气道), and breathing. In minor emergencies，first aid may prevent a victim's condition from turning worse and provide relief from pain. First aid must be   administered as quickly as possible. In the case of the Critically injured, a few minutes can make a difference between complete recovery and loss of life.

    First­aid measures depend upon a victim's needs and the provider's level of knowledge and skill. Knowing what not to do in an emergency is as important as knowing what to do. Improperly moving a person with a neck injury, for example，can lead to permanent spinal (脊柱的) injury and  paralysis (瘫痪)．

    Despite the variety of injuries possible, several principles of first aid apply to all emergencies. The first step is to call for professional medical help. The victim, if conscious（有意识的）, should be reassured that medical aid has been requested，and asked for permission to provide any first aid.  Next，assess the scene, asking other people or the injured  person's family or friends about details of the injury or illness，any care that may have already been given, and preexisting conditions such as diabetes (糖尿病) or heart trouble. The victim should be checked for a medical bracelet (手镯) or card that describes special medical conditions. Unless the accident scene becomes unsafe or the victim may suffer further injury，do not move the victim.

    First aid requires rapid assessment of victims to determine whether life­threatening conditions exist. One method for evaluating a victim's condition is known by the acronym(首字母缩写词)ABC，which stands for：

    A—Airway: Is it open and clear?

    B—Breathing: Is the person breathing? Look, listen, and feel for breathing.

    C—Circulation: Is there a pulse? Is the person bleeding externally? Check skin color and temperature for additional indications of circulation problems.

    Nine years ago, a few days before Christmas, I was a director at a company in San Francisco, and I was called into a meeting that was already in progress. That meeting turned out to be my exit interview. I was 64 years old at the time. It wasn't completely unexpected. I signed a pile of papers and left the company.

    So, 40 plus years of employment was over. I had a good reputation and background. Retirement was not a choice for me. I wanted to do something. And then an idea came into my mind, born from my concern for our environment. I wanted to build my own business, designing and producing biodegradable(可生物降解的)packaging from waste. This is called clean technology, and it was really meaningful to me. It could help reduce billions of pounds of single-use plastic packaging wasted each year.

    Five years later, I'm delighted and proud to share with you that our income has doubled every year and we have no debt. Meanwhile, I have a wonderful partner, and we've won more than 20 awards for the work that we've done.

    And I am doing the most rewarding and meaningful work of my life right now. But what I really long for is to find other first-time entrepreneurs(企业家)who are my age. I want to connect with them.

    So I want to do something about that in a few years. I want us to start talking more about people who don't become entrepreneurs until they are seniors. And then connecting all of them across industries, regions and countries—building a community.

Coral reefs (珊瑚礁) as underwater walls can help reduce the effects of hurricanes on coastal communities. This seems unbelievable. It is reported that scientists have discovered that coral reefs are even more effective than man-made sea walls under the water. However, coral reefs are especially easy to be influenced by climate change. Overfishing and pollution have also proved very dangerous to them. Since 1950, half of the world's coral reefs have already been lost. To protect our communities and keep sea ecosystems alive, we need to protect coral reefs right away.

Let's take a closer look at how coral reefs protect us from floods, and how scientists are 1restoring (修复) reefs.

The roles that coral reefs play as underwater walls have long been recorded by scientists. During a Category 3 hurricane in 2015 in Australia, the coral reefs effectively protected the eastern shoreline from flooding. In contrast, the western coasts without coral reefs suffered serious damage. The researchers observed that the shape of coral reefs can break the approaching waves. More recently, researchers at the University of Miami have reached the same conclusion. They used a special lab simulator (模拟装置) to recreate ocean conditions during a Category 5 hurricane. They found that coral reefs could reduce the impact of waves by up to 95 percent!

Because of higher ocean acidity (酸性) and temperature, coral reefs are disappearing and dying out. At the same time, climate change puts weakened coral reefs under more stress. The University of Miami researchers are testing to plant new coral reefs while others are actively looking for effective methods to reduce the acidity of sea water. The governments have also paid more attention to these actions and provided enough money for reef restoration. With these efforts, we may address climate threats to coral reefs and they can carry on protecting our communities.