А и В:
1. in internet chat rooms you can meet a lot of new friends.
2. peoples in these chat rooms can be anonymous and don't show all of their lifes.
3. if you is shy and aren't self-confident enough, it will be easier to talk in internet than in real life.
4. it's easy to find person, who has got same interests with you
5. if you have got complexes about your appearance or lifestyle(this priblem is very circulated to teenagers and young people), you can hide it from interlocutor and just talk.
C и D:
1)a lot of people in the internet are strange and angry, so they can be frightening and disappointing.
2)you can too carried away in this theme and forget about real friends, your family.
3)also in internet chats room you can meet a maniac or argue with dangerous person, after that you can get problems in real live.
4)most of people in internet chats use slang and too many emogji, it isn't good for your vocabulary and language at all.
5)some people show their private information like number of phone, card, address, so they might be vulnerable because there are enough fraudsters in online chats.