【动词不定式】
1.定义：动词 + 不定式
2.用途：
动词不定式在句中可以作句子任何成分.动词不定式的被动形式除了一般形式外还有其完成式和进行式.不定代词是不指明代替任何特定名词或形容词的代词,英语中不定代词有：some（something,somebody,someone,somewhere）,any（anything,anybody,anyone,anywhere）,no（nothing,nobody,no one）,every（everything,everybody,everyone,everywhere）,all,each,both,much,many,（a）little,（a）few,other（s）,another,none,one,either,neither等.
不定代词的作用特别广泛嘚呦!
动词不定式复心中应注意的几个问题
（1）不定式作表语与“be + to do sth.”的异同.不定式作表语说明主语的内容或性质.
His job is to guard.(说明内容)
be + to do sth.(表示按计划要做的事)
（2）带不定式作宾语的词语.
下列词语常不定式作宾语：afford、promise、refuse、expect、hope、learn、offer、wish、want、fail、plan、agree、forget、like、prefer、decide、manage、try、arrange、determine、desire等.
下列动词后可接疑问词+不定式：teach、decide、wonder、show、learn、forget、ask、find、out、advise、discuss等.
（3）如何理解和使用不定式作宾补.
①动词see、watch、notice、hear、listen to、observe、feel、taste、smell、make、let、have等的宾补用动词原形,变被动时要加to,此时的不定式就是主语补足语.
②常用带不定式作宾补的几种情况：
主语 + ask / require / tell / order / force / get / want / like + sb.to do sth.
③主语 + think / judge / suppose / believe / consider /imagine/
consider / feel + sb.+ to be/ to have done
④主语 + call on / upon / depend on / wait for / ask for + sb.+ to do sth.
（4）不定式作定语的特殊用法.
①下列词语后常接不定式作定语：chance、wish、right、courage、need、promise、time、opportunity、way、the first、the second、the last、the only等.
②不定式作定语和所修饰的名词在逻辑上有主谓关系.
There is no one to look after her.
③不定式与被修饰的名词在逻辑上有动宾关系.
She is now looking for a room to live in.
（5）不定式作状语的用法.
不定式作状语,修饰动词,在句中表示行为目的、结果、原因.only to do表示出人意料的结果.
We hurried to the classroom only to find none there .
in order(not)to,so as(not)to用来引导目的状语,enough,too,so… as to do,such + 名词… as to do作结果状语,如:The girl was so kind as to help the old man off the bus.
I’m not such a fool as to believe that.
（6）不定式的完成时的特殊用法.
①表示不定式中谓语动词发生的动作先于主句的谓语动词发出的动作.
The novel was said to have been published.
I regret to have been with you for so many years.
seem、appear、be said、be supposed、be believed、be thought、be known、be reported等动词常用于上面句型.
此外,glad、happy、satisfied、sorry、surprised、disappointed后也接完成时,但要注意与一般时的区别.
I’m sorry to keep you waiting for a minute.对不起,请稍等.（说话时还未等）
I’m sorry to have kept you waiting.对不起,让你久等了.（说话时已等了很久）