Plants are very important living things. Life could not go on if there were no plants. This is because plants can make food from air, water and sunlight. Animals and men can't make food from air, water and sunlight. Animals get their food by eating plants and other animals. Therefore, animals and men need plants in order to live. This is the reason why we find so many plants around us.

    If you look carefully at the plants around you, you will find that there are many kinds of plants. Some plants are large while others are small. Most plants are green.

    Some plants have many small leaves. Others have only a few. There are many kinds of leaves. Leaves are of different shapes and colors.

    Leaves are also different in other ways. Some leaves have long thin parts at the end, we call them leaf stalks, some have short leaf stalks, others even have no leaf stalks. The leaf edges are also different. Some leaves have smooth(平滑) edges. Some have a wave-shaped edges. Others have edges like the teeth of a saw(锯子).

    You know how much your telephone has changed over the past 10 years? Your car will change even more than that in the next 10 years. One of the biggest changes is that cars will drive themselves.

    “We certainly have the technology for it now.”says Andrew Poliak of automotive（机动车辆的）technology supplier QNX.“We expect self-driving cars to be a mainstream thing between 2020 and 2025.”

    The American company Google has been working on self-driving cars for years. These cars are already on the roads in the United States and are truly self-driving. They have to steering wheels（方向盘）or pedals（踏板）. Last week, the police ordered one of Google's cars to stop for driving too slowly on a public road. The car was not breaking any law, so no one was punished.

    Another American company, Tesla, added an “Autopilot” feature to its cars last month. With the Autopilot turned on, the vehicle drives itself. The car will speed up, slow down, brake and drive by itself. You can take over driving any time by turning the steering wheel or touching a pedal. The car uses sensors（感应器）to know when driveway changing is safe and whether it should speed up or slow down.

    Tesla Autopilot is made for cross-country driving. It keeps you in the driveway and helps you avoid hitting other cars. It does not work well on local roads, for it will not stop at a red light or stop sign.

    Reporter Carolyn Nicander Mohr tried the Autopilot feature of a Tesla earlier this month. She had a hard time trusting the car to do what it should do. She thought about disabling the Autopilot feature many times during her trip. She wanted to take control at every bend in the road and hit the brake when the car in front of her slowed down. Yet the car drove perfectly.

    Other companies are working on self-driving cars, too. Marcedes-Benz, Audi, BMW. Volvo and Toyota all have plans for such vehicles.

    The world has a plastics problem. And not just with bottles. Straws (吸管), toothbrushes, toys—all kinds of plastics are placed in landfills. There are 5 billion tons of plastic waste in the world. Landfills have a large part of it. By 2050, they could have 13 billion tons.

    Much of plastic rubbish finds its way into the ocean. Scientists say 165 million tons of plastic pieces are floating around out there. And most plastic won't disappear itself. It will remain in the ocean forever. Whales get caught in plastic fishing nets. Birds die because of eating plastic straws and bottle caps. It endangers ocean life. Plastic rubbish even ends up in the food we eat.

    Governments are realizing that recycling may not be enough. They are taking more actions. Though it is hard work, it is still a solvable problem. In Britain, people are not allowed to use plastic bags except in hospitals. Scotland and several coastal cities in the US stop people from using plastic straws as well. The US alone throws away some 500 million plastic straws a day. That's enough to circle the Earth twice. "Saying no to a plastic straw is an easy way to make a big difference," Diana Lofflin who started www.strawfree.org said. "'Do we really want to pass on to our children a world harmed by plastic?"

    People have found some tasty ways to reduce waste. A company in India made the first-ever spoon that people can eat. You don't have to eat the spoon. You can throw it away. It decomposes (分解) in just a few days. David Edwards, a scientist at Harvard University, designed an eatable bag which can protect the food or drink inside. It is a delicious replacement for plastic ones.