在英语中，当我们对别人提出要求或疑问的时候，使用一般现在时未免语气有些过于直接。比如：“I want to ask you something.” —— 怎样让这句话听上去更客气些？
 
We can use a past tense to talk politely about something in the present.
In English, you can sometimes use past tenses to be less direct and more polite.
I wanted to ask you something.
I hoped you would make lunch.
This isn't the past – 'I want to ask you something now' and 'I still hope you'll make my lunch', but it's less direct.
Using a continuous tense can seem less permanent and also less direct.
I'm thinking you should buy the ingredients.
I'm not planning to help you.
To really distance yourself, you can do both:
I was hoping you were going to make dessert.
I was expecting you to do the washing up.
I'm being unreasonable, but I'm using past and continuous tenses as distancing to sound polite while I do it.
And now, I'm really hungry.
 
用法总结

1. 用过去时谈论现在的事，可以避免过于直接，听上去更礼貌。
I wanted to ask you if you'd make dinner.
I thought you'd go to the shops.

2. 用进行时代替一般时态，可以显得陈述的事件并非永久性的，从而减弱语气。
I'm thinking it'd be better if you went.
I'm hoping you'll do the work.

3. 结合上述两条，用过去进行时，可以进一步弱化语气，可在提出不太合理的要求时使用。
I was hoping you'd lend your car to me.
I was thinking about asking him to get the bill.
I was expecting to use your discount voucher.