Have you ever heard of e-waste, which can be produced every day? How do you deal with your computers, MP4 players and mobile phones when they're broken or you want a new one?

    Most people just throw them away. With the development of electric industry, e-waste pollution has become a serious problem. According to the United Nations, in 2014, people around the world produced 41.8 million tons of e-waste and only recycled 6.5 million tons. The US was the biggest waster, producing 7.1 million tons. China came second, with 6 million tons.

    It's important to pay attention to e-waste. It can either be valuable or harmful, depending on how we deal with it. E-waste is a valuable urban mine. The value of the metals, like gold and silver in the waste around the world, is amazing. And the metals can be reused. But if people throw them away, the toxic chemicals can get into the earth or air, effecting the environment and people's health.

    Apple, for example, now recycle people's used products in China when they are buying new ones. The company will test and repair the used ones and sell them at lower prices. To help reduce e-waste, we can also take computers and phones to see if companies offer recycling programs.

    Twenty years ago in Costa Rica, three girls found a baby sloth（树懒）on a road. The little animal's mother was killed by a car. These girls took the baby sloth to Judy, the owner of a hotel. Judy wanted to help, but she didn't know how to look after the sloth, so she called the zoo. With the help of the zoo, Judy took good care of the baby sloth. She named the baby sloth Buttercup.

    After her success, more people brought Judy wounded sloths or baby sloths they found. Judy then opened a rescue centre（救助中心）. Today, the rescue centre has saved more than 500 sloths. Sloths live in the forests of Central America and South America. They hang on to the trees with  their claws（爪子）. There are two main types of sloths. You can tell them apart by the number of their claws. Sloths hardly move. They spend most of their time sleeping in the trees.

    But now, with the increase of population, human beings（人类）cause a lot of problems for these slow and quiet animals. The main problems is that the forests are becoming smaller and smaller. When trees are cut down, sloths will fall and break themselves. Sloths who live near human beings sometimes are hit by cars or attacked by dogs.

    At the centre, workers care for the injured animals. Their goal is to help the sloths return to the wild when are healthy enough.

    What was discovered by accident? The answer is penicillin(青霉素). It kills germs. By killing germs, it saves lives. Suppose you are sick. You go to a doctor. She examines you. She says you have a "staph" infection(葡萄球菌感染). She gives you some medicine. You take it. The medicine knocks out the staph. Soon you are well. Before penicillin, this would not happen. Staph was almost sure death.

    Everyone wanted a medicine. Laboratories worked day and night. They grew the staph in small dishes. Then they tried to kill it. Nothing worked.

    The laboratory dishes had covers on them. They kept things from falling into dishes. Molds(霉菌)were a big worry. They are always in the air. You can't see them. They're too small .There are thousands of different molds. Molds can make an experiment (实验)fail. That's why dishes are covered.

    Dr. Alexander Fleming was working to kill the staph germ. He worked for years. One day he took a cover off a dish. He looked inside. There was a thick growth of staph germ. There was also some mold. Then he saw something strange. Where the mold was, there was no growth of staph. This is what Fleming probably thought. "By accident, I found a mold to kill the dreaded staph."

    This is how penicillin was found. But here's the real miracle(奇迹). There are thousands of kinds of molds. But only one kind can kill staph. The mold must have fallen into the dish a few days before. The cover was probably off only a few seconds(秒). In those few seconds the right mold fell into the right dish. Another mall might have thrown the dish away. But Fleming was very careful and smart. He understood what the mold did. How lucky the humans were!

    Have you ever heard robot fish? Scientists will put some robot fish into the sea near Spain. These robot fish will help people to detect (探测) the pollution in the water. If the robot fish are able to finish their work successfully, the scientists hope to put them into rivers, lakes and seas around the world.

    The fish are about 1.5 meters long. There will be a detector in their bodies. They can find the sources (来源) of pollution in the water, and then the robot fish will eat part of it. Unlike other robots, they don't need to be controlled by people far away. The robot fish all have an eight-hour battery (电池). They can "swim" in the sea freely and send back information to people on the beach. After their batteries die, they will return by themselves.

    There are five robot fish altogether now. Each costs about 29,000 dollars. They are part of a three-year project between engineering company BMT Group and Essex University in southeastern England.

    "We invented the robot fish creatively. We hope them can find the changes in the sea water and report back the information," said Professor Hu of Essex University. His team is developing the fish.

    Have you ever wished that your life was like a reality TV show(真人秀节目)? Well, like it or not, things might be this way in the future.

    This is because of Google glasses. Glasses are the latest technology from Google. They have more exciting features(特征)than you could possibly imagine.

    For one thing, people who wear the glasses can shoot videos and record the sounds around them. So if your friend is wearing Google glasses, he or she can record your every move and broadcast live on the Internet for the world to see.

    There is a GPS system in the glasses. So if you get lost you can say" OK, Glass, where am I?", and it will find where you are and tell you where you need to 90.

    Google glasses are a bit like a helpful secretary. You can tell them what you want to write in an e—mail and they will type it for you.

    Since April 16, Google glasses have been on the market in small numbers. But by the end of the year anyone will be able to buy a pair for about 2, 500 yuan.

    Some people are not sure whether they find Google glasses cool or not. When someone is wearing Google glasses, it is not easy to see whether or not they are using them.