情態(tài)動(dòng)詞could的用法
could的否定形式是could not,多縮寫為couldn't,兩者通常都讀作[>kudnt].
（1）表示能力,意思是：能,會(huì).
【例】
Could you speak English then?那時(shí)你能講英語嗎?
He said he couldn't follow me.他說他跟不上我.
注意：①could（能）和was/were able to 都表示過去一般具有某種能力.
【例】
He could (was able to) swim very well when he was nine.他九歲時(shí)就很會(huì)游泳.
②was (were) able to 可以表示過去某時(shí)有某種具體的能力并且實(shí)際上可以做到,但could表示過去的習(xí)慣能力.
【例】
Although the driver was badly hurt,he was able to explain what had happened.司機(jī)雖受重傷,但仍能說明發(fā)生了什么事.
（2）表示可能性,意思是：可能.
【例】
That big cinema can seats 2,000 people.那家大電影院能坐2,000人.
He said he couldn't come.他說他不能來.
（3）提出請(qǐng)求、疑問或看法（could是虛擬語氣,代替can,在時(shí)間上與can沒有區(qū)別,只是語氣比can委婉.can語氣直爽、肯定）.
【例】
----Could you let me have your passport?
----Yes,here it is.
—看看你的護(hù)照好嗎?
—行,這就是.
（4）表示驚異、不信等情緒（用于疑問和否定句中,此時(shí)could與can用法相同,無時(shí)間上的差別,用could語氣緩和,情緒要弱）.
【例】
Who could have taken them?誰會(huì)把它們拿走了呢?
She couldn't have left so soon.她不可能這么快就走了.
（5）表示與事實(shí)相反的情況（用于虛擬語氣）.
【例】
How I wish I could go with you!我多么希望和你們一道去!
would的用法
1) 用于提出提議或邀請(qǐng)
例：Would you like to change a seat?It's warmer here.（您要不要換一下座位?這里暖和些.）
Would you prefer a hardback edition?（您要不要買一本精裝本?）
2) 用于提出客氣的要求或請(qǐng)求：
例：I would like you to fetch that document for me now.（我想請(qǐng)你現(xiàn)在就幫我把那份文件取來.）
I would like to know more about your plan.（我想更多地了解一下你的計(jì)劃.）
3) would you mind + doing句型通常用于表示請(qǐng)求對(duì)方做一件有一定麻煩的事情,語氣一般都非常客氣.注意回答時(shí)通常是肯定的,以表示愿意做所要求的事情.
例：Would you mind filling in this form?（請(qǐng)您填一下這張表.）
Would you mind repeating what you just said?（請(qǐng)把剛才的話重復(fù)一遍好嗎?）
4) 用于委婉地表示自己的意見：
例：I would think the journey will take something like two weeks.（依我看,這次旅程大約需要兩個(gè)星期.）
I would look at the problem a little differently.（我對(duì)這個(gè)問題的看法略有不同.）
5) 用于表示過去經(jīng)常性的行為或動(dòng)作：
例：The retired captain would sit hours on end watching ships sailing past.（退休的船長(zhǎng)經(jīng)常坐在海邊觀望過往的行船,一坐就是幾個(gè)小時(shí).）
He would go to bed strictly at 9,and on Sundays would not have lunch anywhere except in that restaurant.（他總是嚴(yán)格地9點(diǎn)上床睡覺.星期日總在那家飯店吃午飯.）
參考資料：http://222.180.11.3:8082/viewstaticres/SysContent7/d1/dd3/ddd110/754420319310/754420319310.htm