1. Just as every coin has two sides, cars have both advantages and disadvantages．
2. Compared to/ In comparison with letters, e-mails are more convenient.
3. When it comes to computers, some people think they have brought us a lot of convenience. However,...
4. Opinions are divided on the advantages and disadvantages of living in the city and in the countryside.
5. As is known to all/ As we all know, computers have played an important role/part in our daily life.
6. Why do you go to university? Different people have different points of view.