The Internet has been perhaps the greatest innovation in information technology. It has become an important tool with many advantages. First, the Internet is a treasure house of information and knowledge on any topic. It is common practice now to search the web for resources and information for homework, office presentations? work projects and studies, etc. Second, there are more and more massive open online courses (MOOCs) . These MOOCs make it possible for people to carry out their learning any place around the world, and any time around the clock. As long as the learners have access to a digital device which is linked up to the Internet, they can. enjoy browsing pages or watching video lectures. In. doing so, they have opportunities to learn from professors they otherwise would not be able to access. Third, entertainment is one of the leading reasons people like the Web. Listening to music, playing games, watching movies, following the latest news about famous sports stars, movie stars and singers and looking into lifestyle websites have become day-to-day activities of many Internet users. One cannot imagine a social life without QQ or WeChat. These social apps have become our means for staying connected with friends, colleagues and family members, and staying in touch with the world. Last but not least, we can shop and do other business online. We can order goods> books, tickets and pay bills without having to leave our homes or offices. 21. The Internet has been perhaps the greatest innovation in _____・