The amount of time kids spend online is a source of frustration for many parents. Initially, parents welcomed the Internet into their homes, believing they were opening up an exciting new world of educational opportunities for their children. However, many parents soon realized that, instead of using the Internet for homework or research, their kids were spending hours exchanging messages with friends, playing online games or talking to strangers in chat rooms.

Maintaining a healthy balance between entertainment media and other activities in their children's lives has always been a challenge for parents. The Internet has made this challenge even more difficult. The engaging nature of Internet communications and interactive games means many children and teens have trouble keeping track of time when they're online.

Unfortunately, parents and teachers are usually not aware that there is a problem until it becomes serious. This is because it is easy to hide what you are doing online and because Internet addiction is not widely recognized by the medical community. And mental health practitioners continue to debate whether this behavior is an “addiction,” with some identifying it as"compulsive behavior."

Children and young people can easily become hooked on online activities such as multi-user games, instant messaging and chat rooms. The most vulnerable children, according to the Computer-Addiction Services at Harvard Medical School, are those who are "lonely and bored or from families where nobody is at home to relate to after school."

Children who are unpopular or shy with peers are often attracted to the opportunities for creating new identities in online communities. Boys, in particular, are frequent users of online role-playing games, where they assume new identities and interact with other players. Although playing these games with other users may appear to be a social activity, for the introverted (内向的) child or teen, excessive playing can further isolate them from friends and peers.

1.Parents feel frustrated at________online.
2.It has always been a challenge for parents to________.
3.The word "addiction" in Paragraph 3 most probably means________.
4.According to Paragraph 5, when some children play too much online role-playing games, they may become________.
5.The author's attitude towards the Internet can be best described as________.