The TV science-fiction series Star Trek no longer looked far-fetched (牵强的) as four men and four women in black space-suits locked themselves into a giant hi-tech greenhouse, known as a ‘biosphere', in the Arizona desert yesterday for a two-year study of the environment.

    As dawn broke over the Santa Catalina mountains, the eight waved goodbye to television cameras. Edward Ross, their multibillionaire sponsor from a Texas oil family, closed the door of the $150 million structure, with its mini-ocean, marsh, desert, savanna, rain-forest and 3,800 plant and animal species designed to allow the team to recreate Earth and its ecosystems.

    The so-called Biosphere 2 is the latest of a dozen environmental projects started by the self-titled ‘ecopreneur'. The project's main aim is to set up a self-sustaining community for possible use in a spaceship or on another planet. The crew members must plant, harvest and process their food on a half-acre farm in the seven-storey glass and metal structure, while conducting a series of experiments.

    ‘We will be custodians (监护人) of our new little world,' said Abigail Mayer, aged 31, a US marine biologist on the team, her voice choking with emotion. ‘It is a brave new step.' Many scientists, however, are more than skeptical. They point out that the largest closed ecosystem which survived more than a few days was smaller than a football. It was developed at the University of Miami and contained only shrimp, algae and other micro-organisms.

    Critics have also accused Mr. Ross of being more interested in producing a profitable theme park than in carrying out serious scientific research. Hundreds of tourists visited the site daily in the summer before it was occupied by the team. They paid $9.95 to enter and all stopped at the souvenir shop.

    Nowadays it's believed that the largest contributors to air pollution are gasoline vehicles. They not only give off harmful gases but also dangerous and heavy metal particles（微粒） that can result in environmental dangers. We can't stop using vehicles and thus stop air pollution right away. However, at least we can look for better replacements so that air pollution can be reduced. According to studies, hydrogen （氢）cars prove to be a better replacement for traditional cars.

    A hydrogen car is a vehicle that uses hydrogen as fuel for its engine to work. There are two types of hydrogen cars. The first one is to use hydrogen as a fuel, and the second one is to use hydrogen fuel cells（电池） to provide power for the car. Hydrogen and oxygen react chemically with each other to produce electricity, thus starting the car.

    There are many advantages of hydrogen cars. For example, hydrogen is available in plenty. Therefore, you needn't worry about a lack of hydrogen. More importantly, no harmful gases are released as by-products .The only by-products are water and a little amount of heat so air pollution is prevented up to a large extent.

    However, there are also some problems with hydrogen cars. For instance, in case of damage, the cost of repairing and replacing fuel cells is high. Worse still, hydrogen is a material which can burn easily, so it can result in a huge explosion of the car.

    The concept of hydrogen cars is relatively new for most people. Research is still in progress to reduce disadvantages and increase advantages. Therefore, hydrogen cars are expected to contribute their bit towards making this planet better and healthier!

    I began cycling in 2004 when I was a poor student. It was dangerous, sure, but cycling is the fastest, cheapest point-to-point form of transport in Melbourne. I own a car now, but that's just for transporting the baby or groceries.

    I hate driving. So it's been quite encouraging watching the growth in cyclist numbers over the past decade. It is estimated that 10,000-plus cyclists enter the CBD (Central Business District) each day, taking pressure off public transport. But as more people take to cycling as a mode of transport, the number of cyclists seriously injured or killed keeps climbing. And that is a sign that our infrastructure (基础设施) is still not good enough.

    Melbourne was once a dream for cyclists-flat, long, wide roads, with plenty of paths along rivers. Now, cycling can be deadly, with roads dominated by cars. I have a friend who broke her back and was lucky to escape paralysis, and others with broken bones. In my time riding, I've been forced off the road by a truck, cut off by four-wheel drives, and told to get off the road.

    These things don't exactly happen to trams and buses, those other slow coaches on Melbourne's roads. No—drivers reserve a particular savagery (残暴行为) for cyclists. And that's a sign of exactly one thing: inadequate infrastructure.

    We shouldn't need to be taught how to coexist in the same narrow space. Drivers and cyclists should be kept apart. The present debate over how to minimize “dooring” is a distraction.

    Dooring is not a legal problem. You cannot legislate (制定法律) it away. Designing bike paths so riders are channelled between moving cars and parked cars is deadly. All it takes is one daydreaming driver to fling open the door and you are gone. That's what happened to the young university student James Cross.

    This year, there are to be new anti-dooring lanes (车道) built on Glenferrie Road, Hawthorn, where Cross died in 2010. But these lanes are not safe. Cyclists must still pass between two rows of cars.

    Here are some professions Americans consider to be the most honest. Maybe the rest of us can learn from what these people do to establish good relationships with others.

    MEDICAL DOCTORS

    Jack Jacob, Age: 44, Fountain Valley, California

    I try to introduce myself in a pleasant way. I sit down. I don't stand. I make good eye contact with the patient and his or her family. Communication skills are key, as well as showing understanding and availability. For a physician, the most rewarding thing is when someone who has seen your work chooses you.

    ENGINEERS

    Chrissy Keane, Age: 41, Crofton, Maryland

    I don't know that being an engineer means you are automatically trustworthy. However, I do think that most engineers like to follow rules and be organized. They tell you what they think, whether you want to hear it or not. Those are important elements in building trust.

    POLICE OFFICERS

    G. M. Cox, Age: 64, Fort Worth, Texas

    As a police officer, I have the best interests of the people I serve in my heart and in my actions and I'm going to treat everyone the same way. I always want to go up to people and speak to them with respect. Don't talk down to them. You have to establish and maintain that trust. Be equal!

    Ask any group of teenagers in the UK what they most like to eat, and foods like pizzas, curries, pasta, burgers and chips are bound to get mentioned and many young people would probably also list hanging out at the local fast food restaurant as one of their favorite pastimes (消遣).

    But what teenagers like to eat is not necessarily what they should be eating. According to the National and Nutrition Survey, far too many young people in the UK between the ages of 14 and 18 consume too much fat sugar and salt in their diet and take in too many calories. Meanwhile their intake of starchy carbohydrates (含大淀粉的碳水化合物), fibre, iron, vitamins and calcium is too low.

    For a growing body, eating foods containing plenty of calcium, such as milk, yoghurt and cheese, is particularly important as calcium is essential for the development of healthy, strong bones. Similarly, foods that are rich in iron are good for young, rapidly developing bodies, so red meat. bread, green vegetables, dried fruit and tonified(使增强体质的) breakfast cereals are also recommended.

    It is during our teenage years that habits of lifestyle can become entrenched (根深蒂固的),so it is crucial (全关重要的)that young people are educated about what foods arc good for them. In 2005, in an attempt 10 change eating habits and open teenagers' minds to new flavours and new tastes, celebrity chef Jamie Oliver launched a "Feed Me Better" campaign. As part of a television series Jamel School drivers, he worked with teachers and cooks in a number of schools across the UK to provide more healthy, nutritious school meal opt ions. Although there was initial resistance from sonic teenagers and parents. the campaign was generally hailed (把...... 誉为)as a huge success and helped to influence governmental policy on nutritional standards for school meals.

    No one expects to end the teenage love affair with fast and junk food but. hopefully, if projects "Feed Me Better" and the government's own "Change for Life" campaign continue to give out the right messages, more young people will understand the importance of balancing occasional treats with healthier food options.

    Why are people interested in eating raw foods or whole foods? One reason is that eating these types of food reduces the risk of acid accumulation in your body.

    Raw and whole foods are usually digested more efficiently than cooked and refined foods. When we cook foods, we destroy the natural enzymes (酶) that are part of the food in its raw form. These enzymes were intended by nature to help us digest the food. When we consume food without these natural enzymes, our bodies either digest the food improperly or allow too many nutrients to be absorbed into the bloodstream. In both instances, the result is obesity. When too many nutrients are absorbed at once, the body grows fat. Improperly digested food moves slowly through the digestive tract, where it becomes increasingly acidic. To protect its vital organs from this acidic waste, the body changes the acid into fat and stores it safely away from the organs.

    Processed foods contain chemical elements, which might confuse the appetite mechanism that tells us when we've had enough to eat; as a result, people often overeat. Processed foods also upset the digestive cycle. The body will either identify these foods as allergens and then store them safely away from the organs as fat, or the remains of undigested food will become acidic and enter the bloodstream as acid waste, which will stick to the blood vessel walls and block the passage of vital oxygen and nutrients heading for the body's cells. The body's metabolism (新陈代谢) becomes inactive, and the result is weight gain and obesity.

    The accumulation of acid in the digestive tract makes digestion increasingly inefficient. When that happens, even healthy foods can become acidic and the food allergies will become more common.

    To stop this vicious circle in its tracks, people need to consume food and supplements that will neutralize the acid already accumulated in body. Eating the right types of raw and whole foods can help. It's also important to restore your enzyme balance. You need to identify and avoid the foods that cause acid accumulation and consume the foods that increase enzyme production. If you truly want to change and help your body heal itself, you need to take an active approach.