2015年職稱英語(yǔ)考試已經(jīng)開(kāi)始備考,本階段應(yīng)該多整理一些基礎(chǔ)詞匯和語(yǔ)法。為此,醫(yī)學(xué)全在線職稱外語(yǔ)頻道特整理了“2015年職稱英語(yǔ)備考語(yǔ)法資料”供您參考,希望對(duì)您有幫助!
2015年綜合類職稱英語(yǔ)語(yǔ)法:八種時(shí)態(tài)的具體用法匯總
(7)過(guò)去完成時(shí)表示過(guò)去某一時(shí)間或某一動(dòng)作發(fā)生之前已經(jīng)完成的動(dòng)作。簡(jiǎn)言之,過(guò)去完成時(shí)所表示的時(shí)間是“過(guò)去的過(guò)去”。
①過(guò)去完成時(shí)由“助動(dòng)詞had+動(dòng)詞的過(guò)去分詞”構(gòu)成。
②過(guò)去完成時(shí)時(shí)間狀語(yǔ)有:by(yesterday),by then,by the end of(last…)或者由when,before等引出狀語(yǔ)從句。有時(shí)句子中會(huì)有already,just,once,ever,never等詞語(yǔ),也會(huì)有for… 或since…構(gòu)成的時(shí)間狀語(yǔ)。如:They had already finished cleaning the classroom when their teacher came.(當(dāng)老師來(lái)的時(shí)候他們已經(jīng)打掃完了教室)/ The woman had left before he realized she was a cheat.(在他發(fā)覺(jué)那個(gè)婦女是個(gè)騙子時(shí)她已經(jīng)走掉了)
③過(guò)去完成時(shí)常用于賓語(yǔ)從句中、after引導(dǎo)的從句中,或者從句是before引導(dǎo)的主句中。如:After I had put on my shoes and hat,I walked into the darkness.(我穿上鞋子戴上帽子走進(jìn)了黑暗之中)/ He said that he had never seen a kangaroo before.(他說(shuō)他以前從來(lái)沒(méi)有見(jiàn)過(guò)袋鼠)