In most parts of the world, many students help their schools make less pollution. They join “environment clubs”. In an environment club, people work together to make our environment clean.

    Here are some things students often do.

    ◆No—garbage (垃圾) lunches. How much do you throw away after lunch? Environment clubs ask students to bring their lunches in bags that can be used (被使用) again.

    ◆No—car day. On a no-car day, nobody comes to school in a car—not the students and not the teachers! Cars give pollution to our air, so remember: Walk, jump, cycle or run.

    Use your legs! It's lots of fun!

    ◆Turn off the water! Did you know that some toilets can waste (浪费) twenty to forty tons of water an hour? In a year, that would fill a small fiver! In environment clubs, students mend those broken toilets.

    We love our environment. Let's work together to make it clean.  

    There are many wetlands in China and some of them have become the world's important wetlands. The Chinese Yellow Sea Wetlands are among them. They are in Yancheng, Jiangsu Province. They are home for many different kinds of animals. The world's largest Milu Deer Nature Reserve is in them. More than 700 Milu deer live freely there. There are not many red-crowned cranes in the world, but every winter you can see some in the Red-crowned Crane Nature Reserve in the Yellow Sea Wetlands.

The temperature in the wetlands is usually neither too high nor too low. There is a lot of rain and sunshine, too. They are really good places for wildlife. Offering(提供) food and home for some special kinds of animals is not the only reason why we need to protect wetlands. Wetlands are important because they also prevent flood. But some people want to change the wetlands to make more space for farms and less space for wildlife.

    Luckily, more and more people are beginning to realize the importance of wetlands and wildlife. Every year, on February 2nd, many activities are held to tell people more about wetlands.

    How much do you know about the bird world?

    Birds use three gaits: walking, running and hopping．

    In walking, the left and the right feet move in turn (轮流)．Each foot is on the ground for more than half the time, so there are more times when both feet are on the ground．In running, each foot is on the ground for less than half the time, and there are more times when both feet are off the ground．In hopping, the feet move almost at the same time．This means that for much of the time both feet are off the ground．

    Middle-sized and large birds walk at low speed and either run or hop at higher speed．Small birds, such as sparrows and swallows, usually do not walk, because walking may be too slow for them．It seems that the more time a bird spends in trees, the more likely it is to hop．Perhaps there is wide space in a tree between one thin branch (树枝) and the next, so walking is not a good choice, while on each small branch there is enough room to set both feet down side by side, so hopping seems to make sense．

    I'm sure you all know how important recycling is. Recycling is when you take old things and turn them into new things. It sounds like magic. But it's actually very scientific.

    On July 20, 1969, Neil Armstrong became the first person to walk on the moon. The space suit Armstrong wore on his lunar mission has come to symbolize courage and human achievement. In 1971, the Smithsonian's National Air and Space Museum(NASM), in Washington, D.C., acquired (获得) Armstrong's suit. It stood proudly on display for visitors to admire, until there were changes in the suit's appearance. "Over time, the suit started to show signs of deterioration," Lisa Young said. Young is an objects conservator (文物修复员) at NASM. It is her job to preserve(维护)historical and cultural objects.

    "Plastics are tricky to conserve," Young says. They tend to degrade (降解)over time. Neoprene is one type of plastic in Armstrong's suit. The material can turn brittle and break into tiny pieces. This would ruin the space suit. NASM, seeking ways to preserve this historical treasure, removed it from display in 2006.

    What causes plastic to degrade in the first place? "Many things," Odile Madden says. Madden is a scientist in California. She explains that sunlight, water, humidity, and dust can cause plastics to degrade. "Some plastics will break down no matter what we do," Madden says.

    Yet history can still be saved. Scientists have found that storing plastics in cooler temperatures, with lower humidity levels, can slow degradation. Young says Armstrong's suit is currently in storage at a temperature of 63°F and a lower relative humidity of 30%. These conditions will be maintained when Armstrong's suit returns to a museum display case in time for the 50^th anniversary of the moon landing.

    Plastic degradation affects art, too. Artist Claes Oldenburg created False Food Selection in 1966.It consists of plastic food displayed in a wooden box. The plastic food used to look real. Now, some of it has flattened and yellowed. Georgina Rayner is a conservation scientist at Harvard Art Museums, in Cambridge. She says the artwork's wooden box produces an acidic (酸的) gas that eats away at the plastic. This speeds up the degradation process. But Rayner is motivated to conserve this artwork and others like it. "Plastics are a part of our history," she says. "It's important to preserve them so that future generations can understand the journey we've taken."