A smart home is a home with a communication network. This network connects devices(装置), such as lights and TV sets, and allows them to be controlled from far away through electrical wiring, mobile phone communication or WiFi over the internet.

    More and more people may start to consider owning a smart home, because it makes life much more convenient. It can help keep your room at a certain temperature. It can record what happens inside the home and send the video to your phone. When you are on vacation abroad, you can use a smart home controller to switch on or off the electricity when necessary. Some smart homes can receive a visitor, allowing him to come in and offering him a drink. They can even feed the cat and water the plants.

    Besides, smart homes are easy to fix. Most smart home technology and devices are wireless and can be set up with a minimum of tools,using only the guiding information. When a problem appears,you can deal with it yourself without paying a professional.

    However, for home-users,the smart home technology is far from perfect.It can be rather expensive to own the technology and the devices. Also, because the smart home system(系统) allow its owner to get home information from anywhere, it leaves the home easy to be attacked by hackers(黑客), who may secretly use or change the information in the system.

Now,many scientists are excited at the future of smart home technology. Imagine being able to get fashion advice from your mirror, or receive food shopping suggestions from your refrigerator. While there are others who worry that those smart devices will make people lazier and lonelier. Whatever it is, one thing is for sure—smart home technology will change the way we live and work.

Radio, telephone and TV are widely used in the world. When you turn on the radio, you can listen. But when you use telephone, not only can you listen to others but also you can chat with them, however, you can't see anything at all. TV is much better than both of them. People can watch TV and listen to it, but they can't take part in what they see.

    Today, some people are using a type of telephone called vision-phone（可视电话）. With it, two people who are talking can see each other. It is better than radio, telephone or TV.

    Vision-phones can be of great use when you have something to show the person whom you are calling. It will be helpful in people's life. Some day you may be able to call up a library and ask to read a book on your vision-phone. You may be able to do some shopping too. Perhaps in the future, people will use vision-phone.

You might have seen beautiful rainbows in the sky before. They form when sunlight falls on water drops in the air. But in fact, moonlight can also create rainbows in the same way. They are called "moonbows". They are similar to rainbows, but they are created by moonlight. 

Moonbows are more unusual than rainbows. Different weather and astronomical (天文学的) conditions have to be just right for moonbows to be created. The moon has to be very low in the sky — only 42 degrees from the horizon (地平线). The moon has to be a full moon or nearly full. The sky must be very dark for a moonbow to be watched clearly — any bright light can obscure it. Water drops must appear in the air in the opposite direction of the moon. Moonbows appear on the opposite side of the moon and usually look white to the human eye. This is because their colors are not bright enough to be noticed by the human eye. 

Moonbows more often appear in some locations around the world. Most of these locations usually have waterfalls, which create thin fog in the air. Some of these locations are the Yosemite National Park in California, Cumberland Falls State Resort Park in Kentucky and Waimea in Hawaii, US. 

Moonbows do really happen. So at a certain time and a certain place, when a moonbow happens to appear, you can't miss it if you're right there.

As teenagers，you are probably too busy to care about your diet and health. It may harm you some day. So if you want to be healthy in the future，please take the following advice. 

First，have a b {#blank#}1{#/blank#} diet. You should eat mostly rice，bread，vegetables and fruit，but a {#blank#}2{#/blank#} eating food that are high in fat，like French fries，hamburgers，or cookies. Besides，it's necessary to have m {#blank#}3{#/blank#} on time and never miss your breakfast. 

Second，drink plenty of water--at least six to eight glasses a day. Do not wait till you feel t {#blank#}4{#/blank#} . Enough water makes your skin look better. 

At last，do exercise regularly. Experts s {#blank#}5{#/blank#} that teenagers should spend at least 30 minutes per day exercising，such as running，swimming，walking or riding your bike. 

If you follow the advice above，you can greatly improve your health. 

They eat wild animals, plants, berries, nuts, and insects. They hunt with bows and arrows. There are lots of dangerous snakes and spiders. It's one of southern Africa's {#blank#}1{#/blank#}places, and there is often no water. Then they have to get water from plants. When they are ill, there {#blank#}2{#/blank#} no hospitals. The people have to get medicine from plants too. 

They are the San, the last people {#blank#}3{#/blank#} in the Kalahari. The San people have another name "bush people". {#blank#}4{#/blank#} lifestyle is very simple, but they know more about animals and plants than most people do. The San people live in small groups of 25-50. They live in huts little "houses". These {#blank#}5{#/blank#} are made of wood and grass. There are no schools for children. Children learn from the {#blank#}6{#/blank#} people in the group. There are lots of things they have to learn so that they can live in a dangerous place like the Kalahari. In the evenings, the group of people often sit around a fire and tell stories. 

The Kalahari is a big area of bushland in the southern Africa. It {#blank#}7{#/blank#} two parts. There is less rain in the southern part than in the northern part, {#blank#}8{#/blank#} the south is drier. There are fewer plants and animals there, and it's {#blank#}9{#/blank#} for people to live. But when it rains at the end of the summer, the land becomes greener and more beautiful. For a few weeks, there are {#blank#}10{#/blank#} of little flowers and even butterflies(蝴蝶)!

Paper cutting is a symbol of Chinese culture. It can date back to the 2nd century CE, when paper {#blank#}1{#/blank#} invented by Cai Lun. As paper became more affordable, paper cutting became one of the most important types of Chinese folk {#blank#}2{#/blank#} . Later, this art form spread to other parts of the world. 

 In the past, every girl was supposed to master it. Most of them were good at{#blank#}3{#/blank#}it, and brides were often judged by their skills. 

 You can learn how to make paper cutting {#blank#}4{#/blank#}. And required tools are simply a piece of paper and a knife or a pair of{#blank#}5{#/blank#}. But it's not easy to master this art because it requires you to be {#blank#}6{#/blank#} , and you need much practice and imagination. The artworks are made {#blank#}7{#/blank#} red paper because red is related to festivities (欢庆) and happiness in Chinese culture. 

These works could be displayed year- round, and they are {#blank#}8{#/blank#}especially during Chinese 

festivals because of their expression of hopes. Every year before Chinese New Year, people decorate (装饰){#blank#}9{#/blank#}houses with the" Fu" character which means good luck, blessing, and happi-ness. They put their" Fu" upside down to express people's {#blank#}10{#/blank#}for the coming of" Fu".