阅读苹果饼的制作过程，然后把图片与制作程序配伍(有2幅多余图片)。

16.{#blank#}1{#/blank#}、17.{#blank#}2{#/blank#}、18.{#blank#}3{#/blank#}、19.{#blank#}4{#/blank#}、20{#blank#}5{#/blank#}.

C

    We humans produce a lot of waste every day．We pour it onto the environment．This waste often gives off gases and dusts into the air．Often．it is harmful both to nature and to our human life．

    Do you know one of the main causes of the large amount of dangerous waste? It is people who do not realize how big a problem it is．Because it can be simply removed and sent to a landfill(废渣填埋场)．The problem is often believed to end there．In addition，industries are not willing to find ways to deal with the dangerous waste．They think it will cost money．Many industries and governments build simple landfills to store waste．They often just pour waste chemicals into nearby bodies of water．Often，the chemicals used for industrial production cause dangerous forms of waste．The amount of these chemicals has increased greatly in the past．It is often difficult and expensive to get rid of them．It is also hard to store them in a safe way．

    Every year, major health problems result from dangerous waste．Sadly, often only after someone has died or become seriously ill，and then the governments will take measures to reduce the levels of harmful waste．

    Some governments have realized how serious the dangerous waste problem is．They are now trying to solve this problem．They are also trying to limit the amount of waste industries．

    Not only governments but ordinary people must work together to solve the problem．We can choose not to buy those products which produce dangerous waste．Many scientists think waste can be reduced at least one third by using technologies and methods．

    What do you usually do on your smartphone? Send text messages, make phone calls or play video games? Now, thanks to a beginner-friendly programming（程序设计） tool, kids can do more than just play games on their smartphones-they can make their own games.

    US high school student Samuel Ndungi spent a few months learning how to make apps（应用软件）for smart-phones.

    "I was really shocked that you could do this on your own," Ndungi said "I thought only people from Microsoft and big companies could do this."

    Ndungi took a class run by his teacher, Michael Braun. In Braun's class, kids learned how to use the beginner-friendly programming tool to program their own mobile apps.

    This tool is called TouchDevelop. It puts basic instructions（基本指令） into blocks of code（代码）, and kids can put them together like Legos to run games, stories and other apps.

    With TouchDevelop, student Tony Huynh learned how to make his own games. "You get to put your own thoughts into the game, like the animals you want, the kinds of backgrounds you would like to see, and so on," he said.

    Another student Shina Williams wrote a program with about 80 lines of code that paints a picture of his childhood Teddy Bear." It's your own creativity, your own mark（印记） of something that's put in there and it stays in there, " she said.

    Coding is more than just a job skill. Children who learn coding also find new ways to think, create and express themselves.

    When we talk about the universe, we mean not only the earth, the sun and the moon, but also the stars and space between them. There are millions of stars in our sky. The sun is one of them. Around it there are eight big planets moving, including the earth. The moon is our nearest neighbor in space. If you look at the sky on a clear night, it is possible to see about 3, 000 stars. They look small, but they are really very big hot balls of burning（燃烧着的）gas. Some of them arc huge（巨大的）, but others are much smaller like our planet Earth. The biggest stars are very bright, but they can only live for a short time. Every day new stars are born and old stars die.

    All the stars are very far away. The light from the nearest star（except the sun）takes more than four years to reach the earth.

    Hundreds of years ago, people used stars, like the North Star, to know which direction（方向）to travel in.

Today you can still see that star.

    We all cry for water when we are thirsty. But do you know, in very hot, dry weather, plants also make very low sounds as if they are crying for help?

    You see, in a plant's stem there are several hundred "water pipes" that bring water from soil all the way up to the leaves. When the ground turns dry, it becomes harder and harder for plants to do this.

    In very hot days, plants have to get any water that they can get.

    Scientists Robot Winter has found out that when plants can get no water, their "water pipes" snap(发出声音). When that happens, the whole plant vibrates(颤动) a little.

    Robot knows that healthy, well-watered plants are quiet. He also knows that dry plants are many insects' favorites and they often attack(袭击) them. How do the insects know which are healthy plants and which are not? Robot thinks that the insects may hear the plants "crying" and they may come to kill them.