1 . When John Todd was a child, he loved to explore the woods around his house, observing how nature solved problems. A dirty stream, for example, often became clear after flowing through plants and along rocks where tiny creatures lived. When he got older, John started to wonder if this process could be used to clean up the messes people were making.

After studying agriculture, medicine, and fisheries in college, John went back to observing nature and asking questions. Why can certain plants trap harmful bacteria (细菌)? Which kinds of fish can eat cancer-causing chemicals? With the right combination of animals and plants, he figured, maybe he could clean up waste the way nature did. He decided to build what he would later call an eco-machine.

The task John set for himself was to remove harmful substances from some sludge (污泥). First, he constructed a series of clear fiberglass tanks connected to each other. Then he went around to local ponds and streams and brought back some plants and animals. He placed them in the tanks and waited. Little by little, these different kinds of life got used to one another and formed their own ecosystem. After a few weeks, John added the sludge.

He was amazed at the results. The plants and animals in the eco-machine took the sludge as food and began to eat it! Within weeks, it had all been digested, and all that was left was pure water.

Over the years, John has taken on many big jobs. He developed a greenhouse — like facility that treated sewage (污水) from 1,600 homes in South Burlington. He also designed an eco-machine to clean canal water in Fuzhou, a city in southeast China.

“Ecological design” is the name John gives to what he does. “Life on Earth is kind of a box of spare parts for the inventor,” he says. “You put organisms in new relationships and observe what’s happening. Then you let these new systems develop their own ways to self-repair.”

2 . Turning soil, pulling weeds, and harvesting cabbage sound like tough work for middle and high school kids. And at first it is, says Abby Jaramillo, who with another teacher started Urban Sprouts, a school garden program at four low-income schools. The program aims to help students develop science skills, environmental awareness, and healthy lifestyles.

Jaramillo’s students live in neighborhoods where fresh food and green space are not easy to find and fast food restaurants outnumber grocery stores. “The kids literally come to school with bags of snacks and large bottles of soft drinks,” she says. “They come to us thinking vegetables are awful, dirt is awful, insects are awful.” Though some are initially scared of the insects and turned off by the dirt, most are eager to try something new.

Urban Sprouts’ classes, at two middle schools and two high schools, include hands-on experiments such as soil testing, flower-and-seed dissection, tastings of fresh or dried produce, and work in the garden. Several times a year, students cook the vegetables they grow, and they occasionally make salads for their entire schools.

Program evaluations show that kids eat more vegetables as a result of the classes. “We have students who say they went home and talked to their parents and now they’re eating differently,” Jaramillo says.

She adds that the program’s benefits go beyond nutrition. Some students get so interested in gardening that they bring home seeds to start their own vegetable gardens. Besides, working in the garden seems to have a calming effect on Jaramillo’s special education students, many of whom have emotional control issues. “They get outside,” she says, “and they feel successful.”

For thousands of years, people have told fables (寓言)     1     (teach) a lesson or to pass on wisdom. Fables were part of the oral tradition of many early cultures, and the well-known Aesop’s fables date to the     2     (six) century, B. C. Yet, the form of the fable still has values today,     3     Rachel Carson says in “A Fable for Tomorrow.”

Carson uses a simple, direct style common to fable. In fact, her style and tone (口吻) are seemingly directed at children. “There was once a town in the heart of America,     4     all life seemed to enjoy peaceful existence with its surroundings,” her fable begins,     5     (borrow) some familiar words from many age-old fables. Behind the simple style, however, is a serious message     6     (intend) for everyone.

    7     (difference) from traditional fables, Carson’s story ends with an accusation instead of a moral. She warns of the environmental dangers facing society, and she teaches that people must take responsibility     8     saving their environment.

The themes of traditional fables often deal with simple truths about everyday life. However, Carson’s theme is a more weighty     9     (warn) about environmental destruction. Carson proves that a simple literal form that has been passed down through the ages can still     10     (employ) today to draw attention to important truths.

Yangko, a rural Chinese folk dance with a history     1     (date) back thousands of years, originates from farming life in ancient times. The dance relates to sacrifices to the farmland god when people prayed for a good harvest. As time passed, the     2     (origin) dance developed, taking in various artistic forms and skills, including opera, acrobatics and martial arts, and eventually turned into the type of Yangko     3     is seen today.

    4     (preserve) this Chinese folk culture, it was included in the inaugural(首批的)items of national intangible cultural heritage in 2006. It is     5     (common) performed in northern China during festivals, especially for Chinese New Year and the Lantern Festival. Performances or competitions     6     (organize) in towns and villages to express people’s joy and their hope for a better life.

Yangko employs drumming, Suona, dancing and singing. Content is based     7     folk stories and legends. Costumes are richly-colored and opera-styled, enabling     8     (character) to be easily identified. During a performance, the actors will dance and sing, following lively rhythms. Highly skilled and interesting acts such as stilt(高跷)walking     9     carrying a wedding sedan chair(花轿)are also included. As a part of traditional Chinese culture, Yangko     10     (concentrate) the group consciousness of the Chinese people, and has outstanding historical and cultural value.

8 . We may weep for the dodo, but could and should we bring this lovely bird back from the dead? De-extinction is the science of restoring lost species and it has been in the news for decades.

The story in modern times began in 1990 when Michael Crichton published his science fiction novel Jurassic Park, in which he imagined a world where scientists were able to bring dinosaurs back to life. Crichton imagined that polymerase chain reaction (PCR) technology could be a way to amplify (放大) tiny quantities of dinosaur DNA and thus build a living embryo.

Sadly, biologists soon realized that DNA in fact breaks down super-fast; even after 100 years, DNA from museum skins of dodos was decayed (腐烂) beyond repair. They could be sequenced (测定序列) using massive computational power, but then only with considerable uncertainty. And even if you capture a DNA sequence, there’s still the problem of how you get living cells to read that sequence and express proteins that make the dinosaur or the dodo.

But why would anyone want to see mammoths, or something like them, roaming (漫游) present-day Siberia? Well, they were undoubtedly amazing beasts. As well as hunting them, our distant ancestors painted their likenesses in caves across Europe. Fascinating as they may be, there's some ecological justification for the project too.

It was this diversity of land surface, broken up by heavy limbs and randomly fertilised by faeces (排泄物), that supported so much flora (植物群). Without the mammoths, that diversity disappeared. Return them and landscapes would once again be with a variety of species, including flowers and bushes.

True, it’s not de-extinction in the sense of bringing a long-dead species back to life. Instead it’s more like making a “dodo” by engineering a modern pigeon, its closest relative, to become huge and flightless. The result would be a big, fatty pigeon that, whether it looked like a dodo or not, would probably fulfil some of its ecological roles.

As a palaeontologist, I would of course love to see living dinosaurs, mammoths and dodos. In some ways, though, I am relieved that the optimistic claims for cloning and genetic technologies have not been borne out. The slowdown gives us time to consider the outcomes—and hopefully avoid some of Michael Crichton’s more fevered imaginings.