如何用英语委婉地“反对别人”？

I don't think so.

我不这么认为。

Sorry, I have a different opinion.

抱歉，我有不同观点。

I can't buy（相当于believe） that. 

我不相信。

I think your opinions are absolutely nonsense. 

我认为你的观点简直是胡扯。

I can't uphold such conduct. 

我不能忍受那样的行为。

A: Jack, what are you doing?

杰克，你在干什么？

B: I'm playing with mud.

我在玩泥巴。

A: You know, you shouldn't do that. I've told you so many times, it's not good for you.

你知道你不应该那么做，我已经跟你说过很多次了，这对你没好处。

B: But I love it, it's really interesting. I love to play it all day.

但我很喜欢啊，真的很有趣，我很想在这里玩一整天。

A: You think too much. You like it doesn't mean you can do it. 

你想太多了，你喜欢它，并不意味着你能这样做。

B: But it was really fun and I didn't think there was anything wrong with it. 

但它真的很有趣，而且我并没有觉得有什么问题。

A: There's no problem with you playing this. But your score is down because of this. Don't you know, you should do your homework right now. 

你玩这个是没有问题，但是你因为玩这个成绩都下降了，难道你不知道吗？

你现在应该立即去写作业。

B: That's boring. I've learned all the knowledge.

那个太无聊了，我已经把所有的知识都学会了。

A: I don't think so. Your teacher told me that you cheated on the final exam which means you don't know anything about it.

我可不这么认为，你的老师之前告诉我，你这次期末考试作弊了，这说明你根本都不会那些知识。

B: You're wrong. I've learned that knowledge. I just don't want to use my brain. 

你错了，我学会了那些知识，我只是不想动脑计算而已。

A: You're a liar. Stop and write your homework. 

你个骗子，赶紧停下去写你的作业。

B: But that's all I want to do right now.

可是我现在只想玩这个。

A: I said no, and I also said that you can play this only if you have done what you should do. 

我说了不行，而且我之前说过，你只有把你应该做的做好才能玩这个。

B: Please give me another five minutes.

请在给我五分钟的时间。

A: No way. Off to （off to表示“出发去做某事”）your homework now. 

不行，写你的作业去。