would 和 should有什么区别？

would和should

would是will的过去式，Would you～?作为情态动词，表示“可以请你～吗?”

should是shall的过去式，作为情态动词时，则表示“应该～”。

1 would的用法(请记住以下几个句型)

Would you have a cup of tea?

可以请你喝杯茶吗?

1.Would you～?和Will you～?

这两个句型皆表示客气的请求、劝说……，但Would you～?更客气些。

Would you tell me the way to the station?

劳驾，您能告诉我去车站怎样走吗?

(回答同《Will you～?》句型)

2.主语+would like to～

表示“想要……”的意思上，与…want to～意思一 样，但用此句型较客气。

I want to ask you a question.

=I''d(I would)like to ask you a question.

我想问你一个问题。

3.Would you like～?

表示请求、劝说，是很客气的说法。

Would you like a cup of tea?

您愿意喝杯茶吗?

Would you like to sing a song?

请唱首歌好吗?

注意

I'd读为〔aid〕

=I would

=I should

=I had

2 should的用法

You should read this book.

你应该读这本书。

1.should(应当、应该)用于所有人称，与ought to～同义。

You should wait a little more.

=You ought to wait a little more.

你应该再多等一会儿。

2.在表示要求、命令时，语气是由should(应该)、

～had better(最好)、～must(必须)逐渐加强。

现在should 或 would 这两个词中的任何一个都可以用于第一人称，表示条件式中的将来： 
If I had known that, I would (or somewhat more formally, should ) have answered differently. 
如果已经知道了这个情况的话，我就（或正规一点用 should ） 不会那么回答了 ， 
2 But in the second and third persons only would is used: 
但在第二人称或第三人称中只用would ： 
If he had known that, he would (not should ) have answered differently. 
如果他知道那个情况的话，就（不能用 should ） 不会那么回答了。 
3 Wouldcannot always be substituted for should, however. Should is used in all three persons in a conditional clause: 
但是Would并不是总是能由 should 代替。 Should 在三种人称的条件从句中都可以用： 
if I (or you or he ) should decide to go. 
如果我（或 你 或 他 ） 决定要去。 
4 Should is also used in all three persons to express duty or obligation (the equivalent of ought to ): 
Should用于这三种人称的表示职责和义务的句子中（相当于 ought to ）： 
I (or you or he ) should go. 
我（或者 你 或者 他 ） 应该去 。