過去完成時(shí)

　　用法：在過去的時(shí)間里，兩個(gè)動(dòng)作中，發(fā)生在前的哪個(gè)動(dòng)作要用過去完成時(shí)。

　　結(jié)構(gòu)：had+過去分詞

　　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.

　　★ 特殊疑問句

　　What had she done?