Waste can be seen everywhere in the school. Some students ask for more food than they can finish and others often forget to turn off the lights when they leave the classroom. They say they can afford these things. But I don't agree with them.

    Waste can bring a lot of problems. Although China is rich in some resources, we are short of others, such as fresh water. It is reported that we will have no coal or oil to use in 100 years. Think about it. I think we should say no to the students who waste things every day. Everybody should stop wasting as soon as possible.

    In our everyday life, we can do many things to prevent waste from happening. For example, turn off the water taps when we finish washing, turn off the lights when we leave the classroom and try not to order more food than we need. Little by little, everything will be changed. Waste can be stopped one day if we do our best to form the habit of saving.

    Clothes are traditionally made of natural materials, such as cotton, leather and wool. They are all from plants or animals, but that doesn't mean they're friendly to the earth. For example, farmers have to use a lot of chemicals to grow cotton plants.

    Scientists are now looking for new ways to make clothing materials. They hope the new materials are both comfortable and good for the earth. Scientists have worked out how to make materials out of cornhusks (谷壳), chicken feathers and rice straws.

    "They used to be useless things. We always have a problem of how to deal with them," Yang, a scientist says. "Now, we can turn them into beautiful materials. Chicken feathers are better than other things. They have small air pockets like honeycombs. That means it will be very warm if you use them to make a jacket or sweater, and I think more and more people will like to buy these kinds of clothes."

If you look at the top of your phone，you'll usually see a little symbol that says 3G or 4G. The "G" stands for the "generation（代）" of your mobile network. But the symbols will become things of the past after 5G networks fully arrive. Shanghai became the first city in China to start testing 5G networks. 

About 100 times faster than 4G networks，5G lets people download and upload data（数据） faster than ever before. But 5G doesn't just bring faster mobile internet. People can use it for many other things as well. For example，5G helps to make self－driving cars safer. 

5G could also be used to power the Internet of Things（IoT，物联网），that is，a large online network that connects all things and people. Fast internet speeds are the key to developing this technology. 

The IoT could be used in a lot of ways. For example，with IoT，your fridge could automatically（自动地） place an order online for eggs when it finds that there are no eggs left inside. 

It's no secret that there is a space（空间）problem in Manhattan（曼哈顿）.People build up higher and higher buildings because there isn't much land left and there is no room to build out.So people have been building lots of tall and thin buildings.Developers（开发商），the government has made laws（法律）that don't allow developers to build too high buildings.

Oiio Studio thinks about things differently， "what if our buildings were not tall but long？" So the founder of Oiio Studio，loannis Oikonomou（设计）a U﹣shaped building，the Big Bend.It would be a very thin building.It would curve at the top and return to the ground.Oikonomous said he thought of the great idea because he learned from a piece of news.It said that a company made a lift that could travel in curves.So he designed the Big Bend.He thought it as "the longest building in the world".It would be 4000 feet from end to end and would need a different lift system.

"We can't change the law，  ▲   .So if we can bend（使弯曲）our building，" Oiio Studio said.

The Big Bend is just an idea for now.Oikonomous has sent the plans to a few companies，and is looking for developers.If successful，they will build the Big Bend around West 57th Street

It happens every spring. Flowers come out everywhere on the same day. But how do plants "know" when to flower?

For years, it has been a difficult question for scientists. But a US research group may have finally answered it—the secret lies in a protein(蛋白质)called FKF1. This helps plants to know when the days become long and when they get short. Then they can tell the seasons(季节)are changing.

Researchers found the FKF1 protein when they were studying a plant called Arabidopsis. It is sensitive(敏感的)to sunlight, and can be made active by sunlight.

Plants produce this protein every day in the late afternoon all year. If there is no light at this time, for example, in winter when the sun goes down early, the protein won't be active. But when spring comes and the days get longer, the FKF1 protein can be made active by day light and the plants "know" it is time to flower. " If there is light in the late afternoon, plants will know that the days are getting longer and that it is the best time for flowers to come out,"explained Takato Imaizumi, leader of study. But when conditions are poor for growing, such as during autumn or winter when the weather is cold and days are short, plants won' t flower.

Although researchers have only studied how the FKF1 protein works in the Arabidopsis, they believe that it is the same with many other plants, including crops such as rice and wheat.

"If we can control when flowers come out, we might be able to increase crop production," Imaizumi said.

You must know the story of Snow White and the Seven Dwarfs, but do you know the names of the seven dwarfs?

Doc looks the oldest and is always thought as the head of the group. He wears glasses and always thinks up good ideas. 

{#blank#}1{#/blank#} always looks tired. He has the longest beard (胡须) and doesn't talk much. 

{#blank#}2{#/blank#} has the biggest nose and he gets unhappy with others easily as his name says. He dislikes Snow White. But he is the first to save her from danger. 

 {#blank#}3{#/blank#} is the fattest. He laughs a lot and always looks on the good side of things. 

{#blank#}4{#/blank#} looks the youngest and has no bear d at all. He doesn't speak, but he is funny and everyone loves him. 

Bashful is a shy but kind friend. He often covers (盖) his mouth with his hands when Snow White is around.

Sneezy has an allergy (过敏) to flowers, so he's always sneezing (打喷嚏). He is hard- working and always there for his friends. 

Which dwarf do you like best? Why? {#blank#}5{#/blank#}