Reflecting(回忆) on the past about those decisions or actions that can't be reversed(推翻) and being occupied with thoughts of “What if?” is no way to live. But there are a few things in life I'd probably do differently if I had the chance.

    I once majored in architecture — something I had been crazy about for as long as I could remember — and then I suddenly had a change of heart. I made an appointment with my adviser, and told him I was no longer certain I wanted to pursue a career in architecture.

    “Don't give up on your childhood dream!” “He's right,” I thought. “I should just stick it out and I shouldn't disappoint the little girl who once loved architecture.”

    It was awful. I was agonized, holding on to a childhood dream that had long since faded. When I talked with a friend about it a year later, he asked: “Right now, what do you want to do with your life?” That's when I came to the realization that dreams change over time and that you should give up the childhood dream if it's not what you want as an adult. Luckily, it wasn't too late. After some serious thought, I changed my major to journalism. It wasn't something I had always imagined myself pursuing — but at that moment,  it was what I wanted.

    We grow up, and sometimes our dreams change — and that's perfectly OK. You just need to ask yourself every once in a while, “Is this still what I want?” If the answer is no, move on and start chasing a new one.

    Living in the wild can be hard. Finding food and staying safe aren't easy. Each day, animals struggle to survive in their habitats. Not all animals get by on their own. Some animals form a close partnership with other kinds of animals. These pairings are called symbiotic (共生的) relationships.

    In a symbiotic relationship, the animals depend on each other. One animal helps the other meet its needs. Sounds good, right? Not always. Some animals are not very kind to their partners. In some cases, one animal meets its needs but hurts its partner. Take ticks, for example. These insects suck blood to live. To get blood, they attach themselves to other kinds of animals. Ticks can pass germs that cause disease instead of helping their hosts.

    In other relationships, animals don't treat their partners so poorly Both animals benefit from living with the other animal.

    Small animals called cleaner shrimps have found a way of helping fish at coral reefs. As their name suggests, the shrimps clean the fish. They hang out at what scientists call a cleaning station. A fish stops by. Then a shrimp climbs onto the fish and even steps into the fish's mouth. The shrimp uses its tiny claws to pick stuff off the fish's body. That can include dead skin, tiny pieces of food, and wee creatures that can hurt the fish. The fish gets a nice cleaning. The shrimp enjoys a tasty meal offish trash.

    Small birds called plovers are also in the cleaning business. They have big customers—crocodiles. Crocs have long snouts（鼻子）filled with sharp teeth, Cleaning them is tricky. When a croc opens its mouth, the plover hops right in. The croc does not snap its snout shut. Instead, it lets the plover eat small, harmful animals attached to its teeth. The plover gets an easy meal while the croc gets clean teeth.

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    A recent study led by researchers from the National University of Singapore (NUS) has found a clear link between the color of a taxi and its accident rate. An analysis of 36 months of detailed taxi, driver and accident data from two fleets of yellow and blue taxis in Singapore suggested that yellow taxis have fewer accidents than blue taxis. The higher visibility (能见度） of yellow makes it less difficult for drivers to avoid getting into accidents with yellow taxis, leading to a lower accident rate.

    The study was led by Prof Ho. To test whether there was a relationship between the color of a taxi and the number of accidents the taxi had, the research team analysed data collected by the largest taxi company in Singapore. The researchers found that yellow taxis have about 6. 1 fewer accidents per 1,000 taxis per month.

    They also studied the economic effect of changing the color of the entire fleet of taxis to yellow. The Singapore taxi company involved in the study owns about 16,700 taxis in a ratio (比例) of one yellow to three blue taxis. If a commercial decision is made to switch from blue to yellow taxis, 76. 6 fewer accidents will occur per month or 917 fewer accidents per year.

    Assuming an average repair cost of $1,000 per car and a downtime of six days, the color of all taxis to yellow could produce an annual saving of $2 million.

    “We are eager to continue to validate (证实) the findings of our study by looking at the use of yellow in other types of public transport, such as school buses. For example, we hope to compare the accident rates of yellow school buses against those of other colors to find out if yellow is indeed a safer color for school buses. Besides, we' re also interested to look at private-hire vehicles and do a comparison of the accident rates of vehicles that are of different colors explained Prof Ho.

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    When 19-year-old Sophia Giorgi said she was thinking of volunteering to help the Make-A-Wish Foundation (基金会)，nobody understood what she was talking about. But Sophia knew just how important Make – A –Wish could be because this special organization had helped to make a dream come true for one her best friends. We were interested in finding out more, so we went along to meet Sophia listen to what she had to say.

    Sophia told us that Make – A –Wish is a worldwide organization that started in the United States in 1980. ” It's a charity(慈善机构)that helps children who have got very serious illnesses. Make – A –Wish help children feel happy even though they are sick, by making their wishes and dreams come true, ” Sophia explained.

We asked Sophia how Make – A –Wish had first started. She said it had all begun with a very sick young boy called Chris, who had been dreaming for a long time of becoming a policeman. Sophia said lots of people had wanted to find a way to make Chris's dream come true —-so, with everybody's help, Chris, only seven years old at the time, had been a “policeman” for a day. ” when people saw how delighted Chris was when his dream came true, they decided to try and help other sick children too , and that was the beginning of Make – A –Wish, ” explained Sophia.

    Sophia also told us the Foundation tries to give children and their families a special, happy time. A Make-A-Wish volunteer visits the families and asks the children what they would wish for if they could have anything in the world. Sophia said the volunteers were important because they were the ones who helped to make the wishes come true. They do this either by providing things that are necessary, or by raising money or helping out in whatever way they can.

    Health experts are calling for action to increase cancer care and control in the developing world. A medical research paper says cancer was once thought of as a problem mostly in the developed world. But now cancer is a leading cause of death and disability in poor countries as well. Experts from Harvard University and other organizations urge the international community to fight cancer actively, saying it should be fought in the way HIV/AIDS has been fought in Africa.

    Cancer kills more than 7.5 million people a year worldwide. Almost two thirds are in low-income and middle-income countries.

They discover cancer kills more people in developing countries than AIDS, tuberculosis and malaria combined. But the world spends only 5% of its cancer resources in those countries.

    Felicia Knaul from Harvard Medical School was one of the writers of the paper. She was in Mexico when she was found to have breast cancer. She received treatment there and her experience showed her the sharp difference between the rich and the poor in treating breast cancer.

    Felicia Knaul says, “And we are seeing how this is attacking young women. It's the number two cause of death in Mexico of women thirty to fifty-four. All over the developing world, it's the number one cancer-related death among young women. I think we have to again say that there is much more we could do about it than we are doing about it. ”

    Professor Knaul met community health workers during her work in developing countries. They were an important part of efforts to reduce deaths from the cancer. They were able to persuade people to get tested to prevent the illness. The experts say cancer care does not have to be costly. For example, patients can be treated with lower-cost drugs.

Starting a club of some kind at school can be difficult. But with a good idea, some active friends, and the right knowledge, you can pull it off. {#blank#}1{#/blank#}.

Decide whether you really want to start a club. Once you have strong enough support from your friends and fellow students, you're ready to go.

{#blank#}2{#/blank#}. Find an advisor for your club. Pick someone who will help you organize events for your club.

Find a place. {#blank#}3{#/blank#} If you want to do this,  talk to your headteacher to apply (申请) for a classroom.

Decide when to meet. Decide how often your club should meet, and then pick a convenient time and day when most club members will be free.

Advertise your club at school. Make bright, colorful informative posters (海报) that will attract attention. {#blank#}4{#/blank#}.

Plan volunteering events. You can decide on events yourself, or hold a meeting to get your club's opinion. {#blank#}5{#/blank#}

Have fun. What's the point of having a club if it's no fun? Don't take yourself too seriously and be sure to have a sense of humor.