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.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    Until late in the 20th century, most Americans spent time with people of generations. Now mid-aged Americans may not keep in touch with old people until they are old themselves. That's because we group people by age. We put our three-year-olds together in day-care center, our 13-year-olds in school and sports activities, and our 80-year-olds in senior-citizen homes. Why?

    We live away from the old for many reasons: young people sometimes avoid the old to get rid of fears for aging and dying. It is much harder to watch someone we love disappear before our eyes. Sometimes it's so hard that we stay away from the people who need us most.

    Fortunately, some of us have found our way to the old. And we have discovered that they often save the young.

    A reporter moved her family onto a block filled with old people. At first her children were disappointed. But the reporter baked banana bread for the neighbors and had her children deliver it and visit them. Soon the children had many new friends, with whom they shared food, stories and projects. “My children have never been less lonely,” the reporter said.

    The young, in turn, save the old. Once I was in a rest home when a visitor showed up with a baby. She was immediately surrounded. People who hadn't gotten out of bed in a week suddenly were ringing for a wheelchair. Even those who had seemed asleep wake up to watch the child. Babies have an astonishing power to comfort and cure.

    Grandparents are a special case. They give grandchildren a feeling of security and continuity. As my husband put it, “my grandparents gave me a deep sense that things would turn out right in the end.”

    Grandchildren speak of attention they don't get from worried parents. “My parents were always telling me to hurry up, and my grandparents told me to slow down,” one friend said. A teacher told me she can tell which pupils have relationships with grandparents: they are quieter, calmer, more trusting.

    At least five wolves, including one female, have returned to Denmark for the first time in two centuries, a zoologist who has obtained DNA evidence said on Thursday.

    The wolves came from Germany to settle in western Denmark's agricultural region, the least densely populated in the Scandinavian country. Peter Sunde, a scientist at the University of Aarhus, told AFP the wolves must have walked more than 500km. "We think these are young wolves rejected by their families who are looking for new hunting grounds," the researcher added. Scientists have established a genetic profile from the faeces(f粪便) of five wolves - four males and one female - but there could be more. Sunde said researchers had suspected since 2012 that wolves had entered Denmark. "Now we have evidence [including] that there's one female," signalling the possibility of giving birth this spring, he said.

    Proof was also established through the wolves' fingerprints and video surveillance(监视,监督) showed their location, which scientists refuse to reveal out of fear that it will attract hunters."We're following that. The wolf is an animal we're not allowed to hunt so we must protect it," said Henrik Hagen Olesen, spokesperson at the Danish Environmental Protection Agency.Exterminated by hunters, wolves had been completely extinct in Denmark since the beginning of the nineteenth century.

    In other Nordic countries with a higher wolf population, culling(选择性宰杀) the species, protected by the Bern Convention, is under a fierce debate between inhabitants, farmers, hunters, the government, the European Union and wildlife activists.

    Phil White has just returned from an 18,000-mile, around-the-world bicycle trip. White had two reasons for making this epic journey. First of all, he wanted to use the trip to raise money for charity, which he did. He raised ＄70,000 for the British charity, Oxfam. White's second reason for making the trip was to break the world record and become the fastest person to cycle around the world. He is still waiting to find out if he has broken the record or not.

    White set off from Trafalgar Square, in London, on 19th June 2004 and was back 299 days later. He spent more than l,300 hours in the saddle(车座)and destroyed four sets of tyres and three bike chains. He had the adventure of his life crossing Europe, the Middle East, India, Asia, Australia, New Zealand and the Americas. Amazingly, he did all of this with absolutely no support team. No jeep carrying food, water and medicine. No doctor. Nothing! Just a bike and a very, very long road.

    The journey was lonely and desperate at times. He also had to fight his way across deserts, through jungles and over mountains. He cycled through heavy rains and temperatures of up to 45 degrees, all to help people in need. There were other dangers along the road. In Iran, he was chased by armed robbers and was lucky to escape with his life and the little money he had. The worst thing that happened to him was having to cycle into a headwind on a road that crosses the south of Australia. For 1, 000 kilometres he battled against the wind that was constantly pushing him. This part of the trip was slow, hard work and depressing, but he made it in the end. Now Mr. White is back and intends to write a book about his adventures.

    Diana Ross, American pop singer and actress, achieved international popularity, first as the leader singer of the Supremes and later as a solo(独唱的) artist. Diana Ross was born on March 26, 1944, in Detroit, Michigan. She was the second of six children of Fred and Ernestine Ross, who lived in one of Detroit's poor districts. Because her family were closely connected with each other, Ross almost didn't notice the difficult life as she grew up.

    Ross professional career began in 1959, when she joined several neighborhood friends to form the Primettes. The group was renamed the Supremes after signing a recording contract (合同) with Motown late the following year. The group produced many number-one hit singles (热门单曲) on the US Billboard hot 100, including Baby Love, Stop! In The Name of Love and Someday We Will Be Together. In 1967, the group was renamed Diana Ross and the Supremes, foreshadowing（预示） Ross' solo career, which she started in 1970.

    Beginning with Ain't No Mountain High Enough from her first solo album, Ross enjoyed more than ten years of great success with her hit singles. Ross also developed a film-acting career in the 1970s, beginning with a starring role as blues singer Billie Holiday in Lady Sings the Blues and continuing with Mahogany, for which she also recorded the theme song Do You Know Where You're Going To.

    However, in the mid-1980s, Ross saw her career begin to wane. Most of her albums were re-recordings of earlier material. In 2006, she produced I Love You, a collection of love songs by many artists, and she started an energetic concert tour the following year to make the album publicly known. Although you can't find her songs on the US Billboard Hot 100 now, Ross remains popular as one of the leading musical performers of all time.

    When her five daughters were young, Helene An always told them that there was strength in unity (团结). To show this, she held up one chopstick, representing one person. Then she easily broke it into two pieces. Next, she tied several chopsticks together, representing a family. She showed the girls it was hard to break the tied chopsticks. This lesson about family unity stayed with the daughters as they grew up.

    Helene An and her family own a large restaurant business in California. However, when Helene and her husband Danny left their home in Vietnam in 1975, they didn't have much money. They moved their family to San Francisco. There they joined Danny's mother, Diana, who owned a small Italian sandwich shop. Soon afterwards, Helene and Diana changed the sandwich shop into a small Vietnamese restaurant. The five daughters helped in the restaurant when they were young. However, Helene did not want her daughters to always work in the family business because she thought it was too hard.

    Eventually the girls all graduated from college and went away to work for themselves, but one by one, the daughters returned to work in the family business. They opened new restaurants in San Francisco and Los Angeles. Even though family members sometimes disagreed with each other, they worked together to make the business successful. Daughter Elisabeth explains, "Our mother taught us that to succeed we must have unity, and to have unity we must have peace. Without the strength of the family, there is no business."

    Their expanding business became a large corporation in 1996, with three generations of Ans working together. Now the Ans' corporation makes more than $20 million each year. Although they began with a small restaurant, they had big dreams, and they worked together. Now they are a big success.