3 . Goffin’s cockatoos, a kind of small parrot native to Australasia, have been shown to have similar shape-recognition abilities to a human two-year-old. Though not known to use tools in the wild, the birds have proved skilful at tool use while kept in the cage. In a recent experiment, cockatoos were presented with a box with a nut inside it. The clear front of the box had a “keyhole” in a geometric shape, and the birds were given five differently shaped “keys” to choose from. Inserting the correct “key” would let out the nut.

In humans, babies can put a round shape in a round hole from around one year of age, but it will be another year before they are able to do the same with less symmetrical (对称的) shapes. This ability to recognize that a shape will need to be turned in a specific direction before it will fit is called an “allocentric frame of reference”. In the experiment, Goffin’s cockatoos were able to select the right tool for the job, in most cases, by visual recognition alone. Where trial-and-error was used, the cockatoos did better than monkeys in similar tests. This indicates that Goffin’s cockatoos do indeed possess an allocentric frame of reference when moving objects in space, similar to two-year-old babies.

The next step, according to the researchers, is to try and work out whether the cockatoos rely entirely on visual clues (线索), or also use a sense of touch in making their shape selections.

6 . The connection between people and plants has long been the subject of scientific research. Recent studies have found positive effects. A study conducted in Youngstown，Ohio，for example, discovered that greener areas of the city experienced less crime. In another，employees were shown to be 15% more productive when their workplaces were decorated with houseplants.

The engineers at the Massachusetts Institute of Technology(MIT)have taken it a step further changing the actual composition of plants in order to get them to perform diverse，even unusual functions. These include plants that have sensors printed onto their leaves to show when they’re short of water and a plant that can detect harmful chemicals in groundwater. ＂We’re thinking about how we can engineer plants to replace functions of the things that we use every day,＂explained Michael Strano, a professor of chemical engineering at MIT.

One of his latest projects has been to make plants glow(发光)in experiments using some common vegetables. Strano’s team found that they could create a faint light for three-and-a-half hours. The light，about one-thousandth of the amount needed to read by，is just a start. The technology, Strano said, could one day be used to light the rooms or even to turn trees into self-powered street lamps.

In the future，the team hopes to develop a version of the technology that can be sprayed onto plant leaves in a one-off treatment that would last the plant’s lifetime. The engineers are also trying to develop an on and off＂switch＂where the glow would fade when exposed to daylight.

Lighting accounts for about 7% of the total electricity consumed in the US. Since lighting is often far removed from the power source(电源)-such as the distance from a power plant to street lamps on a remote highway-a lot of energy is lost during transmission(传输).Glowing plants could reduce this distance and therefore help save energy.

8 . Race walking shares many fitness benefits with running, research shows, while most likely contributing to fewer injuries. It does, however, have its own problem.

Race walkers are conditioned athletes. The longest track and field event at the Summer Olympics is the 50-kilometer race walk, which is about five miles longer than the marathon. But the sport’s rules require that a race walker’s knees stay straight through most of the leg swing and one foot remain in contact (接触) with the ground at all times. It’s this strange form that makes race walking such an attractive activity, however, says Jaclyn Norberg, an assistant professor of exercise science at Salem State University in Salem, Mass.

Like running, race walking is physically demanding, she says, According to most calculations, race walkers moving at a pace of six miles per hour would burn about 800 calories(卡路里) per hour, which is approximately twice as many as they would burn walking, although fewer than running, which would probably burn about 1,000 or more calories per hour.

However, race walking does not pound the body as much as running does, Dr. Norberg says. According to her research, runners hit the ground with as much as four times their body weight per step, while race walkers, who do not leave the ground, create only about 1.4 times their body weight with each step.

As a result, she says, some of the injuries associated with running, such as runner’s knee, are uncommon among race walkers. But the sport’s strange form does place considerable stress on the ankles and hips, so people with a history of such injuries might want to be cautious in adopting the sport. In fact, anyone wishing to try race walking should probably first consult a coach or experienced racer to learn proper technique, she says. It takes some practice.

The Meredith family lived in a small community. As the economy was in decline, some people in the town had lost their jobs. Many of their families were struggling to make ends meet. People were trying to help each other meet the challenges.

Mrs. Meredith was a most kind and thoughtful woman. She spent a great deal of time visiting the poor. She knew they had problems, and they needed all kinds of help. When she had time, she would bring food and medicine to them.

One morning she told her children about a family she had visited the day before. There was a man sick in bed, his wife, who took care of him and could not go out to work, and their little boy. The little boy -his name was Bernard-had interested her very much.

“I wish you could see him,” she said to her own children, John, Harry, and Clara. “He is such a help to his mother. He wants very much to earn some money, but I don't see what he can do.”

After their mother left the room, the children sat thinking about Bernard. “I wish we could help him to earn money,” said Clara. “His family is suffering so much.”

“So do I,” said Harry. “We really should do something to assist them.”

For some moments, John said nothing, but, suddenly, he sprang to his feet and cried, “I have a great idea! I have a solution that we can all help accomplish(完成).”

The other children also jumped up all attention. When John had an idea, it was sure to be a good one. “I tell you what we can do,” said John. “You know that big box of corn Uncle John sent us? Well, we can make popcorn(爆米花), and put it into paper bags, and Bernard can take it around to the houses and sell it.”

10 . Molai grew up in a tiny village in India. The village lay near some wetlands which became his second___________. He learned the value and beauty of _________ there from a very young age.

When he was 16, Molai began to notice something _________ happening around his home. A flood had hit the area earlier that year and the _________ it caused had driven away a number of birds. _________, the number of snakes had declined as well. He _________ that it was because there weren’t enough trees to protect them from the _________. The solution, of course, was to plant trees so the animals could seek _________ during the daytime. He turned to the _________ department for help but was told that nothing would grow there. However, Molai went looking on his own and __________a nearby island where he began to plant trees.

________ young plants in the dry season was ____________for a lone boy. Molai built at the __________ of each sapling(幼树)a bamboo platform, where he placed earthen pots with small holes to____________ rainwater. The water would then drip(滴落)on the plants below.

Molai __________ to plant trees for the next 37 years. His efforts have resulted in 1,360 acres of naturally-grown land that has become home to many plants and animals.