1、In my opinion/ view, ...
2、It is widely believed that / commonly accepted that ...
3、There are a number of reasons why ...
4、Firstly/Secondly/Thirdly, ...
5、On the one hand, ..、On the other hand, ...
6、To sum up/In conclusion, ...
7、As a result/ Consequently/ Therefore, ...
8、It can be concluded that/ It is obvious that ...
