When you’re not at home, many worries may start to crowd your mind. Did I turn the light off? Did I lock the door? With a smart home, you can keep away from all of these worries.

A smart home is a home with a communication network. This network connects devices, such as lights and TV sets, and allows them to be controlled from far away through electrical wiring(线路), 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 turn 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. When a problem appears, you can deal with it yourself. 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 allows 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 their 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 fridge. 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.

Would you like to live in a city where buildings turn the lights off for you, and self- driving cars find the nearest parking space themselves? Although might sound a little far from you. Irving in a "smart" city like this could happen sooner than you think.

Great changes have taken place in towns that we have lived in for centuries, while completely new cities are being built. One such place is the city of Songdo. Every home there will have a "telepresence" system（远程遥控系统）allowing users to control the heating and locks, take part in video meetings and receive education, healthcare and government services. Around the city, escalator（自动扶梯）will only move when someone is on them, and offices and schools will all be connected to the system.

The great mind behind Songdo is from the company Cisco. In fact, technology companies around the world such as IBM, Siemens and Microsoft are already in the business.

About 75% of the world's population will live in cities by 2050, so cities will need to be more modern to deal with the coming problems "Making cities smarter is one way out, and I think this will in turn make cities greener, " said Dan Hill, head of a research company.