Smoking is harmful. But as soon as you quit the habit, everything will be OK, right?

    Wrong

    New research has found that even if you give up smoking, the damage it has done to your genes(基因) will stay there for a much longer time. In the research, a team of US scientists studied the blood of 16,000 people. Among them, some were smokers, some used to smoke, and the rest were non-smokers. Scientists compared their genes and found that more than 7,000 genes of smokers had changed—a number that is one-third of known human genes.

    According to NBC News, both heart disease and cancer are caused by genetic changes. Some people may have had the changes when they were born, but most people get them in their day-to-day lives while doing things like smoking.

    When you stop smoking, a lot of these genes will return to normal within five years.

    This means your body is trying to heal (治愈) itself of the harmful effects of smoking. But the changes in some of the genes stay for longer. They can stay for as long as 30 years. It's almost like leaving a footprint on wet cement (水泥)—it will always be there, even when you've walked away and when the cement becomes dry.

    Although the study results may make people unhappy, there is a bright side: the findings could help scientists invent medicine to treat genetic damage caused by smoking or find ways to tell which people have heart disease or cancer risks.

    If you could have one superpower, what would it be?

    Dreaming about whether you would want to read minds, see through walls, or have superhuman strength may sound silly, but it actually gets to the heart of what really matters in your life.

    Every day in our work, we are inspired by the people we meet doing extraordinary things to improve the world.

    They have a different kind of superpower that all of us possess: the power to make a difference in the lives of others.

    We're not saying that everyone needs to contribute their lives to the poor. Your lives are busy enough doing homework, playing sports, making friends, seeking after your dreams. But we do think that you can live a more powerful life when you devote some of your time and energy to something much larger than yourself. Find an issue you are interested in and learn more. Volunteer or, if you can, contribute a little money to a cause. Whatever you do, don't be a bystander. Get involved. You may have the opportunity to make your biggest difference when you're older. But why not start now?

    Our own experience working together on health, development, and energy the last twenty years has been one of the most rewarding parts of our lives. It has changed who we are and continues to fuel our optimism about how much the lives of the poorest people will improve in the years ahead.

    Last month, the president of the Maldives, Mohamed Nasheed, held an underwater meeting. The purpose of the ocean floor conference is to highlight the effects of global warming on his island nation.

    The Maldives, located in the Indian Ocean, is the lowest-lying country on Earth. Melting glaciers and polar ice are causing sea levels to rise, putting the Maldives and other low-lying areas at risk of being swallowed by the sea within the next 100 years.

    What can be done? Scientists and leaders from 190 nations will try to figure that out at the United Nations climate change conference next month. The main goal of the meeting is to come up with a new climate agreement for 2012 and beyond. That is when the existing plan, the Kyoto Protocol will expire. The agreement was created in Kyoto, Japan, in 1997. Since then, it has been ratified(正式批准) by 190 nations. The countries promised to limit the amount of greenhouse gases, such as carbon dioxide, which they produced each year.

    The debate over who should cut greenhouse emissions has been going on for years. The US has been hesitant to reduce emissions unless fast-growing nations such as China and India also reduce their use of fossil fuels. In recent months, China has taken steps to be greener. But India has been unwilling to change. It argues that it is unfair for rich nations to ask poorer countries to cut down on emissions.

    While world leaders work on a plan in Copenhagen, there are many things you can do to help the planet. You can save fuel by walking or biking instead of riding in a car. You can start a recycling program in your community. You can plant trees. Trees absorb carbon dioxide from the air and give off oxygen.

    Flying for a long time, you finally arrive at the place where you can relax—your hotel room. Now you throwyour bag on the bed, turn on the TV and watch an international news programme on a satellite channel probably from UK or the USA.

    The main international broadcasters are BBC World and CNN. With an audience of over 1.5 billion people, these are popular channels that offer good-quality news programmes. In both companies, the journalists are experienced writers that produce journalism of a high standard.

    However, there are alternative news channels which people watch because they want a less traditional or non-Western view on world events. Russia Today and Al Jazeera International, an Arabic company, are international channels that broadcast in English. Both companies say they give a fresh view on big stories, and their experienced journalists often report from places where Western journalists do not work, and so they give us stories that we don't normally see.

    The Internet offers more variety. OneWorldTV is an Internet site where you can find stories about the developing world and human rights, rather than the usual stories about US politics and business. The writers for this company are often local people who write the stories for free. This non-professional journalism is increasing, and it certainly offers more choices.

    This increase in citizen journalism means that you can write the news, too. Main news broadcasters often use photographs and stories that members of the general public send to them, especially when there is a dramatic breaking news story. Besides this, some blogs are popular sources of news, and the website NowPublic lets you write stories using information you can get from anywhere, including sites like Youtube, Flickr and Twitter.

    Adopting (领养) a new pet should be an exciting and rewarding experience. But just as all families are different, so are all pets. Learn what to consider before you find your new furry family member.

    All pets require their owner's time, so Theisen, an expert in pet care, says how much time you can give to the pet is the top thing to consider. "If you adopt a 4-year-old cat, she's not going to need the same amount of care as a 9-week-old dog". says Theisen.

    Like dating and finding the perfect partner, you want a pet that shares your interests and activity levels, particularly if you're looking for dogs. "Consider activity levels in the family," says Theisen. "If you're a couch potato, or in other words, a homebody, look for a pet that matches that activity level."

    Some dogs, like Dalmatians and Terriers, can be loud and noisy and demand a more active lifestyle and room to be outside; they might not fit as well in close living situations as more sedentary pets. The Humane Society of the United States encourages potential owners to research books and websites and talk to other pet owners when considering adopting a new pet.

    Theisen says that potential owners should go beyond the first impression of loveliness and watch how the animals interact with them. "There are dogs that will jump to the gate to meet you," says Theisen. "And there are dogs that sit there with their sad doggy eyes — you know they're not going to be high-energy dogs".

    Some exotic pets, like tortoises and parrots, are likely to live longer than dogs and cats — and even their human owners. They can also grow to be much larger than they were when they first came to live with their owners. Owners should make sure that their living situations should be continually updated and also prepare for the animal's future.

    Global warming is the process of earth's atmosphere heating up. Over the last 100 years, the average temperature of earth's atmosphere has gone up 1 Fahrenheit. The weather has not changed exactly the same way in every area of the planet. But scientists think that the rise in average temperature is already affecting the earth, s climate.

    Many scientists now believe that global warming is caused by cutting down trees, producing more trash, and polluting the environment are some of the reasons that the temperature has gone up. Many scientists believe that the biggest causes of global warming are new human technologies that release greenhouse gases into the atmosphere.

    The greenhouse effect is not new. Certain gases in the atmosphere, like carbon dioxide, nitrous oxide and methane, prevent heat energy from escaping back into space. In the past, the climate didn't change much because nature produced just the right amount of greenhouse gases to deal with it.

    Today, most scientists are pretty sure that the rising temperature can't be blamed on nature. Ever since the industrial revolution in the 1700s, humans have relied on machines for daily life. And many of those machines give off a lot of greenhouse gases. An increase in the release of greenhouse gases from human activities is throwing nature off balance.

    The climate is a very complicated thing, but many scientists agree that the rising atmospheric temperature has already damaged the environment. Sheets of ice, called glaciers, are melting in Antarctica and other parts of the globe. As glaciers break off and melt into the oceans, they are adding warm water to the oceans and causing the sea level to rise.

    Over the past last 100 years, the sea level has risen 6-8 inches around the world. That means land along the coasts is beginning to disappear under water. Bigger and warmer oceans are also adding to other weather problems caused by pollution in the atmosphere. Some places have received more rain, others have had bigger storms and a few areas in the world have experienced unusual droughts.