1. Some people think that …. To be frank, I can not agree with their opinion for the reasons below.
2. For years, … has been seen as …, but things are quite different now.
3. I believe the title statement is valid because….
4. I cannot entirely agree with the idea that …. I believe….
5. My argument for this view goes as follows.
6. Along with the development of…, more and more….
7. There is a long-running debate as to whether….
8. It is commonly/generally/widely/ believed /held/accepted/recognized that….
9. As far as I am concerned, I completely agree with the former/ the latter.
10. Before giving my opinion, I think it is essential to look at the argument of both sides.