1.As is often the case…由于通常情况下…

2.But the problem is not so simple.Therefore 然而问题并非如此简单，所以……

3.But it's a pity that… 但遗憾的是…

4.For all that…对于这一切…… In spite of the fact that…尽管事实……

5.However , the difficulty lies in…然而，困难在于…

6.not(that)…but(that)…不是，而是

7.As has been mentioned above…正如上面所提到的…

8.In this respect, we may as well (say) 从这个角度上我们可以说

9.However, we have to look at the other side of the coin, that is… 然而我们还得看到事物的另一方面，即 …

三、结尾句型

1.I will conclude by saying… 最后我要说…

2.Therefore, we have the reason to believe that…因此，我们有理由相信…

3.Therefore, in my opinion, it's more advisable…因此，在我看来，更可取的是…

4.It can be concluded from the discussion that…从中我们可以得出这样的结论

5.From my point of view, it would be better if…在我看来……也许更好