2)in; 3)at; 4)on; 5)in; 6)in; 7)at; 8) at
1. No
2. To discribe advantages and disadvantages of having a mobile phone.
3. On the other hand, To sum up, Firstly, What is more, To begin with, For example, However
4. In the last one
5. I belive
6.Formal style(но это не точно)
Прочитай короткий параграф и исправь ошибки. Тони