Sample answer：

　　Some people might think computer is one of the most important inventions in the last century. But I'd say television. Since the invention of TV, human history has started a new page. First, TV allows people to learn about what's going on in the world. With such information, they are able to get a better understanding of the world they live in. What's more, TV provides a lot of interesting programs that many people enjoy after a long day's work. Its visual effect makes people feel less stressed and more relaxed. Most important of all, Television has a great influence on the way people think and talk.