1、In my opinion, it is essential to...
2、As far as I am concerned, I firmly believe that...
3、It is widely known that...
4、Undoubtedly, it is (not) a wise decision to...
5、There is no doubt that...
6、In conclusion, I would like to say that...
7、It is worth noting that...
8、It is easy to see that...
9、Despite the fact that...
10、It is commonly believed that...