We all need a healthy environment, but we produce waste every day and it does harm to our environment. Though we are young, we can still do something to help. In fact, even the simplest everyday activities can make a real difference to the environment. Here are some ideas for you to live a green life.
   Remember these three words: reduce, reuse and recycle. Reduce means “use less”. Don't waste things. This saves money and reduces pollution and waste going into the environment. Before we buy something new, think if it is really necessary or maybe the old one will be just as good! When we do buy things, choose local products if possible, and try not to buy too many things from abroad.
   Reuse means “use again”. Use things for as long as possible. When we buy things, make sure that they last a long time. We should take care of them so that they will last, and we should repair them if we can instead of throwing them away and buying new ones. Don't use a paper cup or a paper bag. It's better to use a china cup and a lunch box because you can use them again.
   Recycle means “change things into something else”. Although it takes energy to change something into something else, it's better than throwing things away or burning them. Find out what can be recycled in your neighbourhood and take part in recycling programmes. We should also buy products made from recycled materials, such as recycled paper, to help save trees.
Title:{#blank#}1{#/blank#}to Live a Green Life

    Every object has weight. But the center of its weight is not always in the middle of the object. If the top of an object is heavier than its bottom, it will fall over easily. We say that its center of gravity is high. But if the bottom is heavier, it won't fall easily. Then we say that its center of gravity is low.
    Look at the first picture. This empty box must fall over, because its center of gravity (C) is not above the line of its bottom (AB).
Now look at the second picture. There is some heavy iron in the bottom of this box. It will not fall, because its center of gravity is above its bottom.

    Building an app is a big project. If you want to build the next great smartphone app, you need a plan. First, think about the kind of app that you want to build. Will your app be a game? Will it be for business? Then make a schedule(日程安排)for building the app. You need plenty of time for research before you are ready to build.

    Now you're ready to make the app. Building an app is like a puzzle(拼图)with many different parts. You can build it yourself or find a company to help you. There are many videos and websites that can teach you to build one. Some websites provide "building blocks" for app developers. As you build, you pick blocks from the website and put them in your app.

    After you build your app, you need to check it carefully. Look for bugs. Most apps have several problems to fix. Show your app to people. Ask their opinions. Mike sure everything works before letting people download it. There are so many tools that can help you build apps. Having the right tools will make the work easier. Now almost anyone can make a new app.

    Since the first person walked on the moon in 1969, technology has greatly helped space exploration. In recent years scientists have built a special robot to accompany astronauts on space missions (任务). Because this robot looks and moves like a person, scientists call it a humanoid robot. The latest model of the humanoid robot is known as R2, short for Robonaut 2.

    R2 was first launched into space on February 24, 2011. It was built by the National Aeronautics and Space Administration (NASA) and the car producer General Motors (GM).

    R2 weighs 330 pounds and costs $2.5 million to build. It has arms and a head- filled with vision equipment—but no legs. Its "brain", or computer, is in its stomach. R2's arms can hold 20 pounds. Each bendable finger has 5 pounds of grasping force. R2's hands are also skillful. Since its hands are shaped like human hands, R2 can use human tools to complete tasks traditionally performed by astronauts." Astronauts absolutely have their day packed from the minute they wake up until they go to bed. If Robonaut can provide just an hour's worth of relief to the astronauts doing something they don't want to do, that would make it worth it right there," says Nic Radford, the deputy project manager of R2.

    One advantage of working with R2 will be that ii can't complain about its work! Astronauts will also appreciate the fact that the robot can perform its duties without constant supervision (监管). R2 can be assigned a task and then checked on periodically. If R2 does not complete a task correctly, astronauts will be able to make minor adjustments to adapt (适应) the robot's behavior so that the task gets done right.

    R2 is still in the design stage of development, which means that scientists are frequently testing it and looking for ways to improve it. Right now, humanoid robots do not have the protective equipment needed to work outside the space station. As technology advances, humanoid robots will be able to help astronauts with dangerous tasks as well as routine ones.

    In the future, humanoid robots will be astronauts' eyes in space, going to places considered too difficult or unsafe for astronauts to explore. Some of them will be mounted on wheels to explore the surface of planets or asteroids (小行星). The robots will be able to send back videos and help astronauts gather information about the atmospheres of these places.

    One outcome of using these humanoid robots will be a greater understanding of the interaction between humans and robots. NASA engineers believe that when humans and robots combine forces and work together, the results will be better than what either could achieve alone. John Olson, a director at NASA headquarters in Washington, D.C, says that the project will allow us to go farther and achieve more than we can probably even imagine today.

    A 22-year old British student has invented a mobile fridge that could save millions of lives across the world.

    Will Broadway's "Isobar" has been designed to keep vaccines(疫苗) at the ideal temperature while they are being sent in developing countries. And Will doesn't plan to make money from his creation. His purpose is to get vaccines to people who need them, which is why he won't be trying to get a patent(专利). Will's Isobar has won him the James Dyson Award that challenges young people to "design something that solves a problem".

    Present methods of transporting vaccines can lead to the vaccines freezing(冻住) before reaching their places in developing countries, but the Isobar keeps a temperature of 2 to 8 degrees for 30 days.

    Will's invention is expected to save the lives of 1.5 million people across the world, a number he says is "amazing". Having now finished college education, he is making an effort to take the Isobar into production. "I would be hands-on, all the way through it, knowing that it works," he says. "It's amazing to just give it a go, even in my back yard, and see the potential(潜能) of the technology."

    The product has been designed to transport vaccines, but already Will sees the possibility of other medical uses in the developing world and beyond. "Blood donations, organ transplants(器官移植)- if they get trapped in traffic, you still use cold bags that really aren't good enough for a long time," he says.

    There is also a possible, non-medical use of the Isobar. "It would be a great thing to take on a five-day trip where you have no power," he says. But he insists vaccine transportation is the primary function(功能) of his invention.

    Every year on 15th October, over 200 million people around the world take part in Global Handwashing Day. But why do we have a day for something we do all the time? Well, research shows that not enough people often wash their hands with soap. Experts believe that this leads to the deaths of millions of people every year.

    Sidibe, a public health expert says soap is the most beautiful invention in public health. Washing your hands with soap can have a huge impact on reducing (减少) the spread of diseases. Handwashing with soap prevents babies from getting ill and keeps children healthy in school.

    However, washing hands with soap does not happen as often as you might think. This is partly because there aren't enough resources (资源) in poorer countries, but it's also because for many people, handwashing is simply not part of their everyday life. It's not easy to get people to change habits they learned in early childhood -- but this is what Global Handwashing Day wants to do.

    In 2008, the Indian cricket team joined around 100 million Indian schoolchildren in washing their hands to promote (促进) the first ever Global Handwashing Day. Every year since then, many different events have been held around the world. In 2014, Global Handwashing Day was used in the fight against Ebola, a very serious disease, with events held in affected (受感染的) African countries.

    Today, local and national leaders continue to use the day to spread the message about the importance of clean hands. The hope is that handwashing becomes a necessary part of people's lives and improves the health of millions around the world.