Here is an excerpt from an article about Social Networks: There is no denying the terrible and addictive appeal of social networks because of its very modern, useful, friendly, and user-friendly features that always put the user at the center. Do you think there is someone who is so good to you that they are always with you, always "caring, asking" what do you think today, how is your mood? [...] Who always helps you to share your most beautiful and sparkling images; keeps you connected to the outside world; help you express your personality, your own identity? Who is the bridge to help you study, develop your career, cooperate with important partners?... The person who always "loves and honors" you in such a virtual fashion can only be a social network. never mind. Therefore, the number of participants using social networks has increased rapidly, creating extremely crowded online communities with many utilities but also extremely complicated by its "virtual" side. .

(Excerpt from daidoanket. vn newspaper dated June 30, 2019)

a, What is the main content mentioned above?

b, Present your thoughts on the idea that: Social networking is a double-edged sword. (My answer is already ½ page).

c, As a smart user of the net, please share methods to use it effectively without being turned into a slave or victim of it.