Special trees that grow faster, fight pollution, produce better wood, and even sense chemical attacks are being planted by scientists in the US. When 40 per cent of Hawaii's US$14 million-a-year papaya industry was destroyed by a virus five years ago, work began on creating genetically engineered trees. Researchers successfully introduced seeds that were designed to resist the virus.Since then, more and more people have been testing genetically engineered trees.Some researchers put special bacteria into trees to help them grow faster and produce better wood.Others are trying to create trees that can clean polluted soil.Meanwhile fruit farmers are looking for trees that are strong enough to resist worms, and paper companies want trees that produce more wood and therefore more paper. The Pentagon even gave the researchers US$500,000 this year after they developed a pine tree that changes its colours if it senses a chemical attack.So far, the poplar, eucalyptus , apple and coffee trees are among those being engineered.All this can be done today because we have a better understanding of tree genomes . However, some people fear that the genetically engineered trees will cause dangerous results.They are worried that the new trees will breed with natural species and change the balance of the forest environment. "It could be destructive," said Jim Diamond, an environmentalist. "Trees are what is left of our natural environment and home to many endangered species." But researchers insist that science could give nature a fighting chance against both natural and man-made dangers.They hope to answer the critics by stopping the new trees from breeding, so their effect on the environment can be controlled. What caused the American scientists to work on special trees? A) Tree genomes are mapped out so scientists know how to improve trees. B) Great numbers of trees have been lost due to attacks by viruses. C) Researchers successfully introduced seeds designed to resist the virus. D) They think science could give nature a fighting chance against both natural and man-made dangers.
B
Mary Moe may look like an average grandmother.But she is not.She just learned how to fly an airplane,a dream she has had since she was a little girl.But Mary Moe could not find time to make her dream come true.At age 34,she was just too busy to think about flying a plane.Lessons were costly.Everything seemed to be working against Mary.So her dream had to wait. Mary Moe has done a lot during the past 91 years.For much of that time,she wanted to fly,but never had the chance--until now. Ms.Moe learned about Wish of a Lifetime, a non-profit organization.Its goal is to change the way our society thinks about aging and older adults.Sally Webster works for the group.She said Ms.Moe's wish is one of hundreds they receive each year. Wish of a Lifetime helps older people to enjoy a dream.It also sends the message that it is never too late for a dream.But Ms.Webster says it also wants to send another message to society that older Americans can achieve things just like younger Americans can. Susie Danick also believes in this goal.She founded TAD Relocation,a business that helps senior citizens when they move.Ms.Danick gave $5,000 to the Wish of a Lifetime to help seniors realize a dream.Mary Moe was one of them. Mary Moe received three flying lessons.And on the big day of her first flight,her family and friends all came to cheer her on.Mary's success made everyone around her excited and proud.It was just a great event,a great day.Flying teacher David Waksberg says she was very calm,which is always important when you're flying. It is never too late to spread your wings and try something new.You are never too old to try to make your dreams come true. From Mary Moe's success,we can know she is _ . A) determined B) stubborn C) unrealistic D) delicate
A
Q: I always avoid going on field investigations with the toxics team, unless it's ly necessary. It's not that I mind the hard work, or am afraid of coming into contact with toxic substances. What I fear is quickly losing hope about the work I do. However, doing field research with the toxic team, all I see and feel is filth---nothing else. Even if I close my eyes, I can smell the smell of food processing, rotting organic waste from paper mills and chemicals from clothing manufacturers. One morning, I went to investigate a discharged pipe to document and collect samples of pollutants secretly being emitted by a textile mill. I had to work with the utmost secrecy in order to avoid being discovered by the textile mill. I dipped a long measuring pole into the large polluting pipe to measure the volume of polluted water being emitted. But the surface of the water, covered in oil and filth, made me feel as if to vomit . All of a sudden, I felt someone hit me on my back, it frightened me so much that I almost fell into the water. I grasped the pole and looked behind me to see an old man standing there. He asked: "Can you catch fish here?" I realized that he thought I was holding a fish pole, so I kept calm and said: "Yes, I heard that there's a kind of small fish living in this water, and it has medicinal benefits." The old man grew quite curious and replied: "That may be. If a fish can survive in water as dirty as this, it must have a lot of resistance. So it wouldn't be too strange if such fish had medicinal benefits." It was clear he was just passing by, so I answered: "Yeah, survival of the fittest. Fish that adapt can survive, just like us humans." He kept talking to me and didn't want to leave. He wanted to see whether or not I would catch the small fish with medicinal benefits. What is the writer of the text most probably? A) A newspaper reporter. B) A researcher about pollution. C) A fisherman. D) A worker of the textile mill.
A: B
When it comes to cultural heritage protection, the Grand Canal of China is probably the world's greatest project of its kind. The big inland waterway system in the north-eastern and central eastern plains passes through eight of the country's present-day provinces. The Canal runs from Beijing in the north to Zhejiang Province in the south. Constructed in sections from the 5th century BC onwards, it was designed as a means of communication in the 7th century AD. The Canal is the world's greatest civil engineering project before the Industrial Revolution. The Grand Canal reached a peak in the 13th century, providing an inland navigation network consisting of more than 2,000 kilometers of artificial waterways, linking five of the most important river basins in China, including the Yellow River and the Yangtze. It entered a bid as a UNESCO cultural heritage site in 2008. The Grand Canal cultural square is located in Beijing's Tongzhou district. Ever since the Yuan dynasty 800 years ago, the Tongzhou section of the Grand Canal has been the life blood of Beijing. Grain and building materials were all transported to meet the endless demands of the big cities. Even today, the Grand Canal plays a major role in the lives of its citizens. "I grew up near the Grand Canal. In the past the waterway was a lot narrower, but now it's nice and wide and bridges are built over it. I think if the bid for world heritage status succeeds, it will greatly make Tongzhou more famous in the world, especially with Tongzhou aiming to be a sub-center of the capital Beijing," a citizen said. The result of the bid is set to be released next week, and no doubt it will certainly make it into the history books if the Canal is listed as a world heritage site. The Grand Canal was in the most glorious time _ . A) when it was aimed as a means of communication B) when it crossed the Yellow River and the Yangtze C) when it was born about six hundred years later D) when it was designed as an artificial waterway
C