在交际用语中，说话人为了表示礼貌或客气，常用过去时态来表达现在的情况。例如：

Would you please do me a favor?

Would you mind if I opened the door?

I’d appreciate it if you could be quiet.

Wouldn’t it be great if you explained the reason to us?

有些动词包括情态动词，其过去时态表示现在的情况，属于一种委婉表达。除了would之外，could和might也同样可以用来表达现在的婉转请求、建议、疑问或看法。例如：

Could you tell me the way to the station? 请告诉我去车站的路好吗？

Could I speak to you in private a moment, John? 约翰，我可以单独跟你说一会儿话吗

Oh, how could you be so stupid? 哎呀，你怎么这么蠢啊！

It's boring to walk all alone. Couldn't you go for walks with your friends? 一个人走路很没意思。你可以和朋友们一起去散步呀？

Might I ask what you're doing here? 我可不可以问一下，您在这里干什么？

You might as well bring me a chocolate next time.你下次最好给我带块巧克力来。

I might well regret it later. 我很可能以后会对此后悔的。

The paper says that it might rain tomorrow. 报上说明天可能下雨。

I have got a lot of books that might interest you. 我有许多书，也许你感兴趣呢。

The drivers, as you might imagine, didn't care much for that. 和想象中的一样，这些司机对此并不太在意。

【比较】

Could I use your telephone? （意味着I'm not sure if you will allow me to use your phone.)

Might I use your telephone? （意味着If I don't break it, would you mind my using your phone?) 

此外，一些表示“想法，愿望”的动词，如：wonder, hope, think, want等，它们的过去时态可以表示现在婉转的想法或愿望。

I was wondering if you could lend me a hand. （是现在的委婉建议）

We hoped you would do us a favor now. （指现在婉转的希望）

I thought you might like this flower.（指现在的情况，但不敢肯定。） 

I wanted to ask you a question now.（担心对方不给回答，属于婉转。）

Did you wish to see me at present? （属现在的委婉请求。）