現(xiàn)在分詞完成式的概念：
從動(dòng)作關(guān)系上看，現(xiàn)在分詞的完成式主要表示發(fā)生在謂語動(dòng)作之前的動(dòng)作；從用法上看，現(xiàn)在分詞完成式主要用作狀語，表示時(shí)間或原因等。
現(xiàn)在分詞完成式的基本用法：
1、表示時(shí)間：
如：Having noted down our names and addresses, the policeman dismissed us. 那警察把我們的姓名和地址記下之后就讓我們走了。
Having found a hotel, we looked for somewhere to have dinner. 在找好旅館之后，我們就去找吃飯的地方。
Having bought our tickets, we went into the theatre. 我們買好票后就走進(jìn)劇場(chǎng)。
Having packed up her things, she went to book her ticket. 她收拾好行李之后就去買車票。
注：這樣用的現(xiàn)在分詞通�？梢赞D(zhuǎn)換成時(shí)間狀語從句。
如：Having finished her work, she went home. =After she had finished her work, she went home. 她干完工作就回家了。
2、表示原因：
如：Having been there once, she knew the place quite well. 由于去過那兒一次，她對(duì)那地方很熟悉。
Having invited him here to speak, we'd better go to his lecture. 我們邀請(qǐng)他來這兒講演，所以我們最好去聽講。
注：這樣用的現(xiàn)在分詞通�？梢赞D(zhuǎn)換成原因狀語從句。
如：Having been there many times, he offered to be our guide. =As he had been there many times, he offered to be our guide. 他曾多次到過那里，主動(dòng)提出當(dāng)我們的向?qū)А?/p>
現(xiàn)在分詞的完成式用作狀語時(shí)，通常位于主句之前，但有時(shí)也可置于主句之后，不過此時(shí)多見于表原因的場(chǎng)合。
如：I didn't feel terribly shocked, having expected all this. 這情況我早已料到，因此我并不感到過于震驚。
I was unable to accept your invitation. having promised to accompany my mother to the concert. 我因已答應(yīng)陪我母親赴音樂會(huì)而不能接受你的邀請(qǐng)。
現(xiàn)在分詞完成式的否定式：
原則上應(yīng)將not置于整個(gè)分詞完成式之前。
如：Not having done it right, I tried again. 我由于沒有做對(duì)，所以又試了試。
Not having finished his work, he could not leave the office. 由于工作沒干完他不能離開辦公室。
Not having received an answer, she decided to write him another letter. 由于沒得到他的回信，她決定再給他寫一封信。
現(xiàn)在分詞完成式用于獨(dú)立結(jié)構(gòu)：
有時(shí)現(xiàn)在分詞完成式可以用于獨(dú)立結(jié)構(gòu)。
如：The dark clouds having dispersed, the sun shone again. 烏云已散去，太陽又普照大地了。
The river having risen in the night, the crossing was impossible. 夜里河水上漲，渡河不可能了。
My turn having comeround, I was ushered into the examining room. 輪到我之后，我就被引入考場(chǎng)。
The last bus havingg one, we had to walk home. 最后一班公車已經(jīng)走了，我們必須走路回家。
使用現(xiàn)在分詞完成式的錯(cuò)點(diǎn)：
現(xiàn)在分詞的完成式一般不用作定語，遇此情況可改用定語從句。
如：你知道有誰丟了一只貓嗎?
誤：Do you know anyone having lost a cat?
正：Do you know anyone who has lost a cat?
我想同打破窗戶的人淡淡。
誤：I want to talk to the person having broken the window
正：I want to talk to the person who has broken the window
注意：若將以上現(xiàn)在分詞的完成式改為一般式也不可以，因?yàn)楝F(xiàn)在分詞作后置定語時(shí)通常只表示與謂語動(dòng)作同時(shí)或幾乎同時(shí)發(fā)生的動(dòng)作，而不能先于謂語動(dòng)作而發(fā)生。
現(xiàn)在分詞一般式與完成式的區(qū)別：
現(xiàn)在分詞的一般式和完成式均可表示已完成或先于謂語的動(dòng)作，但有區(qū)別：現(xiàn)在分詞一般式所表示的動(dòng)作雖然可以先于謂語動(dòng)作，但兩者之間沒有時(shí)間間隔，而現(xiàn)在分同的完成式所表示的先于謂語的動(dòng)作則與謂語動(dòng)作有一定的時(shí)間間隔。
如：Locking the door, she went out. 她鎖上門走了出去。
Having lost his job, he'd begun to interest himself in local voluntary work.他失業(yè)后便開始關(guān)注地方的志愿工作了。
注：有時(shí)兩者意思差不多，可以換用。
如：Tying one end of the rope to his bed, he threw the other end out of the window.
Having tied one end of the rope to his bed, he threw the other end out of the window. 他把繩子的一頭系在床上，另一頭扔出窗外。
但是注意，用現(xiàn)在分詞一般式代替完成式的用法通常只限于現(xiàn)在分詞所表示的動(dòng)作與謂語動(dòng)詞所表示的動(dòng)作之間沒有時(shí)間間隔的場(chǎng)合，比如以下情況就不可隨便替換。
1、當(dāng)換用會(huì)引起語義含混時(shí)。
如：看完了說明書之后，他迅速拿起了滅火器。
不妥：Reading the instructions, he snatched up the fireextinguisher.
正句：Having read the instructions, he snatched up the fireextinguisher.
前面一句用了現(xiàn)在分詞的一般式，給人的印象好像是兩個(gè)動(dòng)作同時(shí)發(fā)生的，容易引起誤解，故宜改用完成式。
2、當(dāng)兩個(gè)動(dòng)作之間有一段間隔時(shí)，必須用分詞的完成式。
如：Having failed twice, he didn't want to try again. 已經(jīng)失敗了兩次，他不想再試了。
3、當(dāng)?shù)谝粋�(gè)動(dòng)作持續(xù)一段時(shí)間時(shí)，必須用分詞的完成式。
如：Having been his own boss for such a long time, he found it hard to accept orders from another. 自己當(dāng)老板已經(jīng)這么久了，他覺得難以聽從別人的差遣。
現(xiàn)在分詞完成被動(dòng)式與過去分詞的區(qū)別：
現(xiàn)在分詞的完成被動(dòng)式有兩個(gè)特點(diǎn)：一是表示完成，二是表示被動(dòng)。
如：Having been bitten twice, the postman refused to deliver our letters unless we chained our dog up. 郵遞員被狗咬了兩次之后要我們把狗拴起來，不然就不給我們送信了。
過去分詞的用法也有兩個(gè)特點(diǎn)：一是表示完成，二是表示被動(dòng)。所以有時(shí)現(xiàn)在分詞的完成被動(dòng)式與過去分詞可以表示相同的意思。
如：(Having been)written in haste, the book has many mistakes. 這書因?qū)懙脗}促，所以錯(cuò)誤不少。
(Having been)born in America, he is proficient in English. 由于他是在美國(guó)出生的，所以英語很好。
有時(shí)雖然所表示的時(shí)間概念相同，但有細(xì)微區(qū)別：
如：Having been shown the lab, we left. 被領(lǐng)著看了實(shí)驗(yàn)室后，我們就離開了。
Shown the lab, we left. 被領(lǐng)著一看完實(shí)驗(yàn)室，我們就離開了。(有一種急促感)
注：以下情況通常用過去分詞，而不用現(xiàn)在分詞的完成式。
1、過去分詞表示先于謂語動(dòng)同發(fā)生的動(dòng)作外，還可以表示與謂語動(dòng)詞同時(shí)(幾乎同時(shí))發(fā)生的動(dòng)作，此時(shí)不可用現(xiàn)在分詞的完成式代替。
如：He came in, followed by his secretary. 他走了進(jìn)來，后面跟著他的秘書。
Convinced that they were going to poison him, he refused to eat anything. 他相信他們要毒死他，所以他拒絕進(jìn)食。
2、當(dāng)過去分詞以表示現(xiàn)在或過去(當(dāng)時(shí))的狀態(tài)時(shí)，也不可用現(xiàn)在分詞的完成式代替。
如：The murderer was brought in, his hands tied behind. 兇手被帶了進(jìn)來，雙手被綁在后面。
3、當(dāng)連用具體明確的過去時(shí)間狀語時(shí)，通常也只用過去分詞。
如：Built in1501, the bridge is over 500 years old. 這座橋建于1501年，已有五百多年的歷史。