如何写英语作文中的主题句

　　The Internet has many advantages. It helps people get more up-to-day information and broaden their horizons and provides them more opportunity to buy and sell goods. But the Internet also has many downsides such as computer radiation, personal information leaks and energy-consuming computer games. In my opinion, we shouldn't addict ourselves to the on-line world but to make use of the Internet in a right way.