根据短文内容和所给中文提示，写出空白处各单词的正确形式。(每空限填一词)

School children wrote letters to keep in (接触) with each other in the past. But now it's very easy for them to do that with the help of mobile phones. They (也) use it to listen to music, play games, (购物) online and many other things. Some even can't go to bed (没有) their mobile phones.

For (父母亲), mobile phones help them to know where their children are and keep them (安全). But they (担心) that children communicate too much with their friends. Teachers think mobile phones are (有害) for school children because they don't listen to teachers in class and they use mobile phones to read stories or watch （电影). Most children think mobile phones bring them a lot of (乐趣) like their friends.