將來完成時(shí)用來表示在將來某一時(shí)間以前已經(jīng)完成或一直持續(xù)的動(dòng)作。經(jīng)常與before+將來時(shí)間或by+將來時(shí)間連用，也可與before或by the time引導(dǎo)的現(xiàn)在時(shí)的從句連用。
一、結(jié)構(gòu)形式
過去完成進(jìn)行時(shí)由“will / shall have been+現(xiàn)在分詞(doing)”構(gòu)成，通常還會(huì)有其他狀語成分表示時(shí)間長短。

二、用法歸納
用法一：表示動(dòng)作從某一時(shí)間開始一直延續(xù)到將來某一時(shí)間，至于是否繼續(xù)下去，要視上下文而定。如：
She will have been having treatment all her life.
她將終生受到治療。

By the end of next month he will have been here for ten years. 到下月底，他在這兒就夠十年了。 By this time next year, we will have been doing business with each other for 20 years. 到明年這時(shí)候，我們的業(yè)務(wù)住來就滿20年了。 By the end of this year he’ll have been acting for thirty years. 到今年年底他當(dāng)演員就滿30年了。
用法二：表示一種經(jīng)常性反復(fù)進(jìn)行的持續(xù)性動(dòng)作。如：
By the end of this month he will have been training horses for twenty years. 到了這個(gè)月底他馴馬就滿20年了。
By the end of this month he will have been climbing mountains for twenty years. 到了這個(gè)月底他登山就滿20年了。
Before turning into 42, Tom will have been jogging for 10 years. 在湯姆滿42歲之前，他堅(jiān)持慢跑10年了。
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