動(dòng)詞不定式：
動(dòng)詞不定式由“to+ 動(dòng)詞原形”構(gòu)成,如：to study, to play,動(dòng)詞不定式雖然不能作謂語(yǔ)動(dòng)詞用,但仍留著動(dòng)詞的特征,它可以帶有所需要的賓語(yǔ)或狀語(yǔ)而構(gòu)成動(dòng)詞不定式短語(yǔ),如：to study hard, to play table tennis.
1. 動(dòng)詞不定式的形式變化：動(dòng)詞不定式有下列時(shí)態(tài)和語(yǔ)態(tài)的形式變化.
語(yǔ)態(tài)式一般式完成式進(jìn)行式完成進(jìn)行式
主動(dòng)to buildto have builtto be buildingto have been building
被動(dòng)to be buildto have been build
2. 動(dòng)詞不定式的基本用法：動(dòng)詞不定式能起名詞、形容詞和副詞的作用,可在句中作主語(yǔ)、表語(yǔ)、賓語(yǔ)補(bǔ)足語(yǔ)、定語(yǔ)和狀語(yǔ)用,如：
（1）作主語(yǔ)：To help each other is good.（動(dòng)詞不定式作主語(yǔ)時(shí),一般可用it作形式主語(yǔ),而將作主語(yǔ)的動(dòng)詞不定式置于句末,如：It is good to help each other.
（2）作表語(yǔ)：My job is to drive them to the power station every day. 動(dòng)詞不定式在系動(dòng)詞be之后作表語(yǔ),與表示將來(lái)時(shí)的be + 動(dòng)詞不定式結(jié)構(gòu)有所區(qū)別,如：Our plan is to set up another middle school for the peasants’ children.我們的計(jì)劃是給農(nóng)民子弟再成立一所中學(xué).（句中的謂語(yǔ)動(dòng)詞為is,動(dòng)詞不定式to set up… 為表語(yǔ),主語(yǔ)為plan,但plan并不是動(dòng)詞不定式的邏輯主語(yǔ),即動(dòng)詞不定式 to set up所表示的動(dòng)作不是主語(yǔ)plan產(chǎn)生的.）We are to set up another middle school for the peasants’ children.我們將為農(nóng)民的子弟再成立一所中學(xué).（句中的are to set up整個(gè)結(jié)構(gòu)為句中謂語(yǔ),主語(yǔ)為we,同時(shí)也是動(dòng)詞不定式to set up所表示的動(dòng)作的邏輯主語(yǔ),即動(dòng)詞不定式to set up所表示的動(dòng)作是由we產(chǎn)生的）.
（3）作賓語(yǔ)：① 作及物動(dòng)詞的賓語(yǔ),如：She wishes to be a musician.；② 作某些形容詞的賓語(yǔ)：可以有動(dòng)詞不定式為賓語(yǔ)的形容詞一般有g(shù)lad, sorry, afraid, pleased, determined, willing, eager, anxious, ready, sure等,如：I am determined to give up smoking.；③ 動(dòng)詞不定式一般不作介詞的賓語(yǔ),但動(dòng)詞不定式之前如有疑問(wèn)詞時(shí),就可作介詞的賓語(yǔ),如：Can you give us some advice on what to do next?
（4）作賓語(yǔ)補(bǔ)足語(yǔ),如：Tell the children not to play on the street. 如果句中的謂語(yǔ)動(dòng)詞為see, hear, watch, notice, have, make, let等,作賓語(yǔ)補(bǔ)足語(yǔ)的動(dòng)詞不定式須將to省去,如：I saw a little girl run across the street.
（5）動(dòng)詞不定式在句中作賓語(yǔ),如帶有賓語(yǔ)補(bǔ)足語(yǔ)時(shí),須先用it作形式賓語(yǔ),而將該動(dòng)詞不定式后置,如：I don’t think it right to do it that way.
（6）作定語(yǔ)：動(dòng)詞不定式作定語(yǔ)時(shí),須位于被其修飾的名詞或代詞之后,如：Is this the best way to help him? 和定語(yǔ)用的動(dòng)詞不定式如果是不及物動(dòng)詞,不定式后面就要用必要的介詞,如：He is the man to depend on. 如果被不定式修飾的名詞為place, time, way,不定式后面的介詞,習(xí)慣上可以省去,如：The old man is looking for a quiet place to live.
（7）作狀語(yǔ)：動(dòng)詞不定式可以作下列的狀語(yǔ)：① 目的狀語(yǔ)： Every morning he gets up very early to read English. 為了強(qiáng)調(diào)不定式表示目的的作用,可在不定式前加in order to或so as to（以便或?yàn)榱耍?但應(yīng)注意in order to位于句首或句中均可,而so as to不能位于句首,如：She reads China Daily every day in order to （so as to） improve her English. 將表示目的的不定式置于句首,也可強(qiáng)調(diào)目的的作用,如：To master a foreign language, one must work hard at it. ② 結(jié)果狀語(yǔ)：They lived to see the liberation of their home town.他們活到親眼見(jiàn)到了他們家鄉(xiāng)的解放.③ too + 形容詞或副詞 + 動(dòng)詞不定式,表示“足能…”的結(jié)果,如：You are old enough to take care of yourself now.
3. 復(fù)合結(jié)構(gòu)不定式：由for + 名詞（或代詞賓格）+ 動(dòng)詞不定式即構(gòu)成復(fù)合結(jié)構(gòu)的動(dòng)詞不定式.其中for本身無(wú)意義.for后面的名詞或代詞是不定式的邏輯主語(yǔ),這種不定式在句中可作主語(yǔ)、表語(yǔ)、賓語(yǔ)、定語(yǔ)或狀語(yǔ),如：It is very important for us to get everything ready for the harvest. 當(dāng)作表語(yǔ)用的形容詞表示不定式的邏輯主語(yǔ)的性質(zhì)或特征時(shí),就用介詞of而不用for引出不定式的邏輯主語(yǔ),這些形容詞一般有g(shù)ood, nice, kind, wise, silly, stupid, foolish, right, wrong, careless, impolite等,如：It is very kind of you to help him every day.
4. 疑問(wèn)詞 + 動(dòng)詞不定式：疑問(wèn)代詞和疑問(wèn)副詞后可加動(dòng)詞不定式構(gòu)成不定式短語(yǔ),在句中可作主語(yǔ)、表語(yǔ)或賓語(yǔ),如：How to prevent them from swimming in this river is a problem.
5. 動(dòng)詞不定式的否定式：動(dòng)詞不定式的否定式是由not + 動(dòng)詞不定式構(gòu)成,如：It’s wrong of you not to attend the meeting.
6. 動(dòng)詞不定式的時(shí)態(tài)形式所表示的時(shí)間關(guān)系：（1）一般式：動(dòng)詞不定式一般式所表示的動(dòng)作是和謂語(yǔ)動(dòng)詞所表示的動(dòng)作同時(shí)發(fā)生,但在多數(shù)情況下,是在謂語(yǔ)動(dòng)詞所表示的動(dòng)作之后發(fā)生,如：We decided to plant more trees this spring.（其后）,They often watch us play table tennis.（同時(shí)）；（2）完成式：動(dòng)詞不定式完成式所表示的動(dòng)作發(fā)生在謂語(yǔ)動(dòng)詞所表示的動(dòng)作之前,如：I am sorry to have kept you waiting.（3）進(jìn)行式：動(dòng)詞不定式進(jìn)行式所表示的動(dòng)作正在進(jìn)行中,而且與謂語(yǔ)動(dòng)詞所表示的動(dòng)作同時(shí)發(fā)生,如：She happened to be writing a letter in the room when I came in.
7. 動(dòng)詞不定式的被動(dòng)語(yǔ)態(tài)用法：如果動(dòng)詞不定式的邏輯主語(yǔ)為這個(gè)不定式所表示的動(dòng)作的承受者時(shí),不定式一般就用被動(dòng)語(yǔ)態(tài)形式,如：What is to be done next hasn’t been decided yet