非限定動詞即非謂語動詞，是那些不能單獨作謂語，在人稱和數方面不受主語限定的，具有名詞、形容詞 和副詞的某些特征的動詞形式，是不定式、分詞和動名詞的總稱。要想掌握非限定動詞，首先要熟悉英語的句 子成分、時態及語態等，然後再了解非限定動詞的特點、形式、作用及區別等。當然還要做些相關的習題。要 著重掌握以下內容。
一.非限定動詞的否定
not須加在非限定動詞之前。加強語氣時用never代替not。
1. 不定式的否定形式：I promised not to be late. You"dbetter not say that again.
2.動名詞的否定形式：Please excuse his not writing to you.
3.分詞的否定形式：Not having done his job, he is notallowed to go out.
4.強調時的否定形式：Though never defeated in battle, theyfinally surrendered.
二.非限定動詞的完成式、進行式完成進行式及被動式
1.完成式表示動作已經(或本應)完成，往往強調其動作發生在謂語動詞的動作之前。
I"m sorry to have woken you up.
He intended to have come yesterday.
Having failed twice, he didn"t want to try again.
2.進行式表示動作正在進行(或反復發生)，有時強調某種情感。
I pretended to be reading the newspaper.
I don"t want you to be forever finding fault with me.
3.完成進行式表示動作一直在進行(或反復發生，往往與表示一段時間的狀語連用。
Having been standing the whole morning,I felt so tired.
I"m sorry to have been troubling you all the time.
4.非限定動詞的邏輯主語是其動作的承受者時，要用相應的被動式。
I want this to be done again.
I object to being criticised so stupidly.
The letter written by Tom was funny.(過去分詞隻有一般式，但自身有被動意義。)
三. 主動式表示被動意義的用法
1.動名詞用于need, require, want(需要)，demand 以及deserve之後要用主動式。
My bike needs repairing. = My bike needs to be repaired.
2.動名詞用于worth之後要用主動式。
The book is worth reading.
3.動名詞在past(超過)、for(適合于)、beyond (超過)等介詞後要用主動式。
Those trousers are past mending.
This is a room for sleeping in.
4.當不定式作定語，主語又是不定式的動作執行者時，能常用主動式。
I have letters to write.我要寫幾封信。(我寫—主謂關系)
5.當不定式作表語，主語又是不定式的動作承受者時，通常用主動式。
The book is easy to read.= It is easy to read the book. (讀書—動賓關系)
四、不定式不帶to的用法
1.不定式用于Why和Why not 之後不帶to。
Why spend so much money?
Why not ask Susan to help you?
2.當介詞except、but前有do、did、does 時， 其後的不定式不帶to。
Can"t you do anything but ask silly questions?(有do，無to)
試比較：There"s nothing to do but wait.
There"s no choice but to wait.(無do，需要to)
3.不定式在had better/rather 、 would rather/sooner, rather/sooner than等短語後不帶to。
You"d better try again.
I"d rather be told the truth than be lied to.
4.不定式作have、make、let、feel、see、watch、notice、 hear、listen to、look at等動詞(短語) 的賓語補足式不帶to，作主語補足語時(即被動語態之後)則要帶to。
Her parents wouldn"t let her go out alone.
I heard him say that he was tired.
試比較：He made me move my car.(作賓語補足語)
I was made to move my car.(作主語補足語)
五.不定式的幾種用法
1.有些名詞要用不定式作定語。如need、decision、right、way、wish等。
You did right to tell me the truth.
He expressed a wish to be alone.
2.名詞或代詞前有best、only、next、last、first時， 要用不定式作定語。
I was the only one to arrive on time.
He"s always the first (person) to come and the last toleave.
3.不定式可與whether或疑問句(why除外)構成復合式，作賓語、主語、表語和同位語。
He"ll tell you what to do.(作賓語)
When to start is undecided.(作主語)
4.進行時後面可跟不定式，卻不能跟動名詞。
It"s starting to rain.
I"m going to tell you a story.
5.有些動詞(短語)要用不定式作賓語或賓語補足語。如hope，decide，expect，manage等。
He hoped to win the contest.(賓語)
註意：不定式不能作hope和suggest的賓語補足語。
We wanted the dinner to taste good.(賓語補足語)
六.動名詞的幾種用法
1.介詞(except，but除外)後面要用動名詞。 尤其要註意介詞to。
What about sending her a postcard?
I"m looking forward to seeing Ann.
2.有些動詞(短語)要用動名詞作賓語。如：avoid、enjoy、finish、mind、suggest等。
He dislikes seeing you with me.
Paula has given up smoking.
3.有些句型要求用動名詞。 如there"s nothing worse than,there"s no, have(no)difficulty(或 trouble)，what"s the use(或point)，have a hard time, be busy等。
It"s no use worrying.
This clock is hardly worth repairing.
試比較：I had difficulty finding it.
It was difficult for me to find it.
4.動名詞前可用名詞或代詞作其邏輯主語，在句首用屬格，不定代詞或短語用通格。
Do you mind my smoking?(在非正式場合可用賓格me 取代屬格my)
George"s(或His)making fun of people got him into serious trouble.(屬格)
I can"t imagine Frank and Mabel paying so much for apiano.(通格)
七.分詞的幾種用法
1.現在分詞通常表示主動或進行的意義，過去分詞通常表示被動或完成的意義。
I found the man standing at the door.(正站著—主動)
The man injured by the bullet was taken to hospital.(已受傷—被動)
2.當主語是分詞的動作執行者時，用現在分詞;若是承受者時，則是過去分詞。
Sitting here, I can see the hills.
Seen from here, the tower is tall.
3.分詞作表語時，表示特徵用現在分詞，表示狀態用過去分詞。
The news was surprising. We were surprised at the news.
4.“名詞(代詞的賓格)+分詞”稱作“獨立主格結構”，其作用相當于狀語從句。
It being Sunday, the library was closed.(相當于As it wasSunday......)
八.非限定動詞的用法辨析
1.當賓語是補足語的行為執行者時，強調動作已完成不定式，強調動作在進行或將出現用現在分詞;若是 承受者時，則用過去分詞。
We saw him leave the house.(已走出)
She noticed him waiting there.(正在等)
He had me swimming in a week.(去遊泳)
I heard her praised then.(受表揚)
2.有些動詞的空語要用動名詞，賓語補足語卻要不定式。 如admit、advise、allow、authorise、encour age 、 forbid 、 permit 、recommend等。
We don"t allow smoking in our house.(用動名詞作賓語)
He doesn"t allow me to use the telephone. (用不定式作賓語補足語)
3.有些詞(組)後面要跟不定式，有些則要跟動名詞。試比較：
I would like to see that film.
Do you feel like going out?
The letter failed to arrive.
He succeeded in solving the mystery.
It took hours (for her) to get it.
He spent hours reading last night.
4.有些詞(組)後面既可跟不定式，又可跟動名詞，但含意不同。如remember、mean、learn等。
I now regret saying what I said.(後悔)
We regret to inform you that we are unable to offer youthe job.(抱歉)
The minister went on talking for two hours.(連續)
Having explained the theory, he went on to show us how todo it.(接著)
5.有些搭配容易混淆。試比較：
To teach is to learn twice.(To do...is to do...)
Teaching is learning twice.(Doing...is doing...)
I prefer driving to travelling by train.(prefer doing...to doing...)
I prefer to drive rather than travel by train.(prefer todo...than do...)
I would prefer to drive there.(would prefer to do...)
I used to live alone.(sb. used to do...某人過去常常...)
The cloth is used to clean the desk.(被動語態)
She is used to driving on the left.(used 可換成accustomed習慣于...)