在英语中委婉表达反对可以采用以下几种方式：

1. 使用“不同意”的委婉说法：

I have to disagree with that.

I'm not quite sure about that.

I see what you mean, but I don't think that's the best approach.

2. 提出不同的观点：

That's an interesting point, but I have a different perspective.

I understand where you're coming from, but I have a different opinion.

While I appreciate your view, I have to take a different stance.

3. 使用“我认为”来引导不同意见：

I think it might be a good idea, but...

I believe that could work, but...

In my opinion, while that might be true, we should also consider...

4. 提出疑问：

Is that the best way to handle it?

Do you think that will really solve the problem?

Is there another possibility we should consider?

5. 使用条件句：

I wouldn't say that's entirely true, unless...

I think it's a good idea, but only if...

While I'm not opposed to that, it would depend on...

6. 提出建议或解决方案：

Maybe we could try...

Perhaps a different approach would be more effective.

I suggest we consider...

通过上述方式，可以在不直接表达反对的情况下，温和地提出自己的不同意见。