阅读下面材料，从每题所给的三个选项（A、B和C）中，选出最佳选项。

Invention 1	These glasses are made from a special liquid(液体). They allow users to adjust the focus(调整焦距) of the glasses until everything is clear. They are designed for children. So they won't buy new glasses every time when their eyesight changes.
Invention 2	The Donkey Bike has a strong steel bar(钢条) running along it. It can carry both a gas can and a pet at the same time when you ride this bike.
Invention 3	This machine looks friendly and is called Little Printer. It can print news headlines, riddles and other things on a roll(卷) of paper. So you can make your own little newspaper with it.

    There are many kinds of food in the world. Scientists know a lot about them. They say that there are some kinds of food people must eat every day. For example, people must eat some green and yellow vegetables. We shouldn't eat too much meat. People also need to eat some fruits, bread and rice. Of course our bodies need some water and milk.

    Scientists say people in different countries and different places eat different kinds of food. They cook food in different ways. Different people eat at different times. In one place, people eat once or twice a day. But in another place, people eat three or four times. The scientists say when to eat and how many times to eat are not important. What we eat is the most important thing.

    Nowadays, the world faces two problems. People in some places, for example, in Africa, are not full. Many people are eating junk food. It's bad for people's health. So it's our duty to make everyone full and make everyone healthy.

D

    When a computer works on a group of programs, it can get very hot. Cooling the computer can cost a lot. So some scientists wonder what would happen if the heat from the computer could be used.

    Large Internet companies (公司）such as Google and Microsoft have thousands of computers. As these computers deal with information, they produce lots of heat, so they need huge cooling systems(系统）. These systems send the heat into the air.

    A company in Holland(荷兰） thinks paying to make the computers work and then paying again to cool them are a waste of energy. So the company developed a special device—the e-Radiator.

    Boaz Leupe, head of the company, says the e-Radiator works as a heating system and saves money. He explains that the energy is used twice—once to heat the home and once to cool the computer and that the users don't have to pay to cool their computers.

    Five homeowners in Holland are testing the heating system in their homes.

    "We pay for the computer using, so, in that way, homeowners get heating for free," Boaz says.

    Jan Visser is one of the homeowners. "If you use the computer more, the e-Radiator produces more heat," he says. "It can't provide enough heat if you don't use your computer often." But he is ready to try it. It's a great help for his family.

    The company says e-Radiators produce heat temperatures of up to 55℃. It says the system could save its users about $440 a year.

    Have you ever stayed in a hotel? Most Chinese hotels often provide guests with things like disposable (一次性的) toothbrushes, toothpaste, shampoo and slippers. Many guests like the idea because they don't have to bring their own. But, if you travel to Beijing, remember to bring your own things. Starting from June, some hotels in Beijing will no longer provide guests with these disposables. They want to ask people to use less disposable things.

    Many disposable things are made of plastic. People throw them away after only using them once. It is a waste of natural resources (资源) and is very bad for the environment. Do you know, one Chinese person makes as much as 400kg of waste a year! Most of that waste comes from disposable things. In Beijing, people throw away about 19,000 tons of plastic bags and 1,320 tons of plastic lunch bowls every year! Plastic can take between 100 and 400 years to break down. So the less plastic we throw out, the better. So, wherever you travel, bring your own things and use them again and again.

    Back at home and school, you can also do something to make our world a better place. Try to do these things in your daily life: Use cloth shopping bags, not plastic ones. After using a plastic bag, wash it out and let it dry. Then you can use it over and over again. Do not use paper cups. At your school canteen(食堂), use your own bowl and chopsticks instead of disposable ones.