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.

    Light and shadow（影子）are friends. They usually go together. We receive light every day. At the same time, we produce shadow.

    Light cannot shine through you. Your body stops it from passing. There is a dark spot on the ground next to you. The light cannot reach the dark spot. This is your shadow.

    At noon the Sun shines over your head. Your body stops very little light from reaching the ground.

    We love light, especially sunlight. Without sunlight, life on the Earth is impossible. Most of us like to stand in the shadow of a tree in summer. But some people are afraid of their own shadow at night. They do not want to walk in a dark street. They do not want to see the shadow either. But still light and shadow usually go together.

    As we know, there are differences between western culture and Chinese culture. We can see differences when we pay attention to the way words are used. Let's look at the words about animals and plants. Most expressions in Chinese about dogs, for example, a homeless dog, a mad dog and a dog catching a mouse, have negative meanings. But in western countries, dogs are thought to be honest and good friends of humans. In English, people use the dog to describe positive actions. For example, you are a lucky dog means you are a lucky person. And every dog has its day means each person has good luck sometimes. To describe a person's serious illness, they say sick as a dog. The word dog-tired means very tired. However, Chinese love cats very much. But in western culture, cat is often used to describe a woman who is cruel.

    The rose is regarded as a symbol of love in both China and some western countries. People think the rose means love, peace, courage and friendship. And the rose is the national flower of England, America and many other countries.

    The words about plants and animals are used in positive or negative ways in different cultures. We can learn about many differences in cultures by comparing how some words are used.