新概念英語(yǔ)作為家喻戶(hù)曉的英文學(xué)習(xí)教材，《新概念英語(yǔ)》在中國(guó)經(jīng)久不衰，影響了好幾代學(xué)習(xí)者。即使以今天的角度來(lái)看，這套出版于幾十年前的教材無(wú)論是在編排體系，題材和題材，詞匯還是語(yǔ)法上都有出彩之處，值得各個(gè)層次的人學(xué)習(xí)。
過(guò)去完成時(shí)
用法：在過(guò)去的時(shí)間里，兩個(gè)動(dòng)作中，發(fā)生在前的哪個(gè)動(dòng)作要用過(guò)去完成時(shí)。
結(jié)構(gòu)：had+過(guò)去分詞
After she had finished her homework, she went shopping.
They had sold the car before I asked the price.
The train had left before I arrived at the station.
After/before引導(dǎo)的時(shí)間狀語(yǔ)從句放在句首要在句子后面加逗號(hào)，如果放在主句后則不用加。
★ 變疑問(wèn)句將助動(dòng)詞移到句首
Had she finished her homework?
★ 變否定句在助動(dòng)詞后面加not
She hadn't finished her homework.
★ 肯定回答及否定回答
Yes, she had. / No, she hadn't.
★ 特殊疑問(wèn)句
What had she done?