1. 表达自己意见
I think that... 我认为... (最简单的表达，也最直接)
It seems to me that... 在我看来... (可以用作表达意见，或者总结或者认可对方说的话)
I would argue that...我是这么看的... (这里面用would来弱化语气)
Just to go along with what you said... 顺着你刚才说的，... (这句话，真的很好用，承上启下。这句话还好在，它使你现在插话看上去很合理，因为你是为了顺着前面的那个人继续说)
Going back to what xxx said... 回到刚才XXX说的，... (同上。不过一般是你已经说了几句，此事，想要与别人刚刚提到过或者蜻蜓点水说的的东西扯上点关系。这句话的好处就是，一能让别人看到我的说法和你是有一致之处的， 二能表现他刚才说的东西你还有印象)
2. 同意或者反对
I agree with you. 我同意你说的。(最简单的)
Building on what XX has just said, ....就刚才XXX说的，...
I am with you..., but [main point]. 我明白你的意思，不过... (这里I am with you不一定表示同意也不一定表示反对，它主要的意思是说"你说的我听懂了/我跟上你说的了)
I follow your logic, but have you thought about/considered this... [main point]...? 你说的我明白了，但是你有没有想过...(和上面一句话的逻辑是一样的)
I see what you are saying, but I'm not sure I would argue that... 我明白你的意思，不过我不确定我的观点与你一致... (和上面两句话的逻辑一样)
With all due respect, I think... 恕我直言，我认为...
3. 谦虚的反对
Correct me if I'm wrong, but isn't [a different topic]...? 如果我说错了，请你们指正，不过是不是...?
I'm not an expert on..., it seems to me that... 我在这方面是外行，在我看来...
I might be wrong, but ... 可能我理解错了，不过...
I suspect that I lack some information about this aspect, but here is my two cents. 可能我对这方面的信息了解不够充分，我的看法是...
I am not sure about this..., you might want to check with Professor X... Would you mind lettingme know what he/she says? 这个我不太确定，或许你可以找XX教授确认一下。到时候麻烦你告诉我一下他是怎么说的，可以吗?
This is one way to look at it. Another way to look at it might be.... 你这是一种看法，我另外还有一种看法是...(这句话通常在别人说了一堆之后，为了引出自己的观点时使用)
