Some international languages are widely used for many purposes. Some minority languages will die out and some nations tend to keep minority languages. I reckon that most common used international languages ease our life quality and communication with different nationalities. On the other hand, we need to help improve minority languages.

    There are many languages in the entire world but two or three minority languages die out each year. Some countries try to save dying languages. For instance, Australian Government created a project to save the language and culture of Maori who are Australian aborigines. And there are other projects to keep minority languages such as American Indian language.

    However, the worldwide job market usually requires candidates who can speak English or other international languages. People who cannot speak lingua franca (共通语) could hardly be promoted at work. For example, some companies need an employee who can deal with foreign companies. So most people tend to learn at least one international language that helps them to find a better job.

    Therefore, world needs one common lingua franca that should be spoken in any country. Consequently, one common language should be a required subject in every school. So anyone speaking one common language can travel without worries to any point of the world and trade their products. People will not be forced to learn many languages.

    In conclusion, we should help minority nations to keep their languages for the cultural diversity. To ease the worldwide communication among nations, we should create a common language and provide courses of it. As a result, no one will face a language issue.

    Looking back on the first twenty years of my life, I feel grateful to have been so healthy and happy. For my happiness, I am grateful to so many people and lucky events, but what have guided me and supported me in my life are my physical health, healthy finances, and my family's happiness.

    Health comes first for me, because without health everything else is meaningless. Imagine starting a career without good health. Imagine starting a family without good health. Imagine achieving anything without good health. Clearly, good health is the first necessary for other part of one's life.

    Good health is not enough to be happy. We still need to have money in today's society. Money obviously pays for basic needs of life — food, housing, clothing — but it is also necessary for other reason like the quality of our education and medical care.

    Next comes the most important thing in having a happy life — our family. It provides the love, joy and support that everybody needs. I love my family with all my heart. I get pleasure from their pleasure. I suffer when they suffer. My family helped me get through the hard times of entrance exams. They comforted and advised me when I had misunderstanding with my friends. More importantly, they have been there to share in my successes in the past twenty years. In summary, all these are what I need and want in this world. As long as I stay healthy, earn enough money, and share both good times and bad times with my family, I will always be the happiest girl in the world.

    The Hong Kong-Zhuhai-Macau Bridge, the world's longest sea-based project, comprises four parts: a 22.9-kilometer steel bridge, two artificial islands, a submerged sea tunnel extending for 6.7 kilometers, as well as leading bridges that connect the bridge to the cities.

    For a bridge project, designers prefer to build all the structure on the ground, and only choose the tunnel when there is no alternative. However, for the HZMB, the most practical design is to integrate bridge, island and tunnel to form a complete cross-sea channel.

    "The Pearl River Estuary （河口）holds a world-level shipping channel. Smooth traffic should be guaranteed. And the location is near the Hong Kong International Airport. With about 2,000 flights taking off and landing at the airport, the bridge cannot be built too high for safety reasons, said Meng Fanchao, chief designer of the project. ^"But you cannot have a submerged sea tunnel without any support. That forced us to build the artificial islands."

    Chinese engineers declared a trail in installing deep-immersed tunnel tubes. There is no model for us to refer to as all the cases are shallow-buried tubes, said Meng.

    "For lack of experience, the installation of the first tube lasted for 96 hours," said Yin Haiqing, deputy manager of the Project Management Department. "Everyone was exhausted when we made it."

    The 6.7-kilometer tunnel is the world's longest submerged sea tunnel.

    Two artificial islands, covering an area of 200,000 square meters, help create a smooth transition between bridge sections and tunnels. Different from traditional island, the engineers put 120 steel cylinders （圆柱）with a 22-meter diameter （直径）into the seabed, make out the shape of an island, and fill the island with soil. It is an innovative way they adopted to build the artificial island, making it firmer, more efficient and friendly to the marine ecology.

    The HZMB provides a fixed link between the two Chinese economic centres Hong Kong and Macau and the mainland of China at Zhuhai.

    You're out to dinner. The food is delicious and the service is fine. You decide to leave a big fat tip. Why? The answer may not be as simple as you think.

    Tipping, psychologists have found, is not just about service. Instead, studies have shown that tipping can be affected by psychological reactions to a series of different factors from the waiter's choice of words, to how they carry themselves while taking orders, to the billl's total.

Even how much waiters remind customers of themselves can determine how much change they pocket by the end of the night.

    "Studies before have shown that mimicry (模仿)brings into positive feelings for the mimicker, "wrote Rick van Baaren, a social psychology professor. "These studies show that people who are being mimicked become more generous toward the person who mimicks.

    So Rick van Baaren divided 59 waiters into two groups. He requested that half serve with a phrase such as, "Coming up!" Those in the other half were instructed to repeat the orders and preferences back to the customers. Rick van Baaren then compared their takehome pay. The results were clear-it pays to mimic your customer. The copycat (模仿者)waiters earned almost double the amount of tips to the other group.

    Leonard Green and Joel Myerson, psychologists at Washington University in St Louis, found the generosity of a tipper may be limited by his bill. After research on the 1,000 tips left for waiters, cabdrivers, hair stylists, they found tip percentages in these three areas dropped as customers' bills went up. In fact, tip percentages appear to plateau (稳定期)when bills topped $100 and a bill for $200 made the worker gain no bigger percentage tip than a bill for $100.

    "That's also a point of tipping," Green says. "You have to give a little extra to the cabdriver for being there to pick you up and something to the waiter for being there to serve you. If they weren't there, you'd never get any service. So part of the idea of a tip is for just being there."

    In the near future, IoT (Internet of Things) will drive huge innovation (革新) in the way our food is grown. Plants will have a "voice", not a human voice, but a voice based on data that can tell people, computers, and machines when, for example, they are thirsty, or need more sun, medicine, etc.

    Take vertical (垂直的) farms, for example. Farming is moving indoors where the growth of plants can be monitored and controlled. The facilities are built vertically, so growing areas can be put in piles. This greatly reduces the amount of land needed for farming.

    From an IoT point of view, vertical farms are connected in two ways. First, small sensors (传感器) in the soil or connected to plants tell a control system exactly how much light, water, and nutrients are needed to grow the healthiest crops. Sensors will also tell vertical farmers when crops are nearing their peak for harvesting at just the right time to make sure it's still fresh when it reaches its final destination.

    Second, vertical farms will be connected to other networks and information systems, including databases that track local demand. For example, local restaurants may input when they need fresh food supplies. And vertical farmers could get that information so they know which crops to grow in what quantities. This type of IoT system would have been unimaginable a generation ago.

    Today, vertical farms are being experimented. Yet, the numbers point to a bright future for the industry, especially as the world's population continues to grow. For example, Green Sense Farms in Chicago is able to harvest crops 26 times a year using 85 percent less energy, one-tenth the water, and no pesticides. A side benefit of lower energy use is lower CO₂ output of two tons per month, with the added benefit of creating 46 pounds of oxygen every day.

    Eating red meat is linked to cancer and heart disease, but are the risks big enough to justify giving up juicy burgers and delicious steaks? Probably not, according to researchers who reviewed data from 12 clinical trials involving about 54,000 people. In a series of controversial papers, the researchers argue that the increased health risks tied to red meat are small and uncertain, and that cutting back likely wouldn't be worth it for people who enjoy meat.

    Those conclusions go against established medical advice. They were swiftly attacked by a group of famous U.S. scientists who took the unusual step of trying to stop the papers from being published until their criticisms were addressed.

    The new work does not say red or processed meats like hot dogs and bacon are healthy, or that people should eat more of them. The team's reviews of past studies generally support the ties to cancer, heart disease and other bad health outcomes. But the authors say the evidence is weak, and that there's not much certainty meat is really the cause, since other diet and lifestyle factors could be at play.

    If the latest example of how divisive nutrition research has become, with its uncertainties leaving the door open for conflicting advice. Critics say findings often aren't backed by strong evidence. Defenders counter that nutrition studies can rarely be conclusive because of the difficulty of measuring the effects of any single food, but that methods have improved.

    Based on their analyses, the researchers said people do not have to cut back for health reasons. But they noted that their own advice is weak, and acknowledged that they didn't consider factors such as animal welfare and the environment. Indeed, the case that meat production is bad for animal welfare and the environment is stronger than the case that it's bad for human health, according to an editorial that accompanies the report.

    Not all of the report authors agreed with its conclusions. Three of the 14 researchers said they support reducing red and processed meats. A coauthor of one of the reviews is also among those who called for a publication delay.

    Those who pushed to postpone publication also questioned why certain studies were included in the reviews while others were left out.

    As for his own diet, Dr. Gordon Guyatt, a member of the international research team that conducted the reviews, said he no longer thinks red or processed meats have significant health risks. But he said he still avoids them out of habit, and for animal welfare and environmental reasons.