1、Infinitive表语主语宾语不定式宾语补足语定语状语1.to do as a subjectThe cat said,“To take roller coaster is terrible.”The cat said,“Its terrible to take roller coaster.”How long did it take you to take roller coaster?How terrible it is to take roller coaster!不定式短语作主语时，可以直接放在句首，但在很多情况下，尤其是在疑问句和感叹句中，往往放在谓语之后，而用先行代词it作形式主
2、语。it作形式主语，不定式作真主语常见句型:a)It is+adj.(easy,important,difficult)+不定式b)It is+n.(a pity,a pleasure,ones duty,a shame)+不定式c)It takes/needs/requires+some time(hours,months,days,patience)+不定式2.to do as a predictive当句子的主语是aim，idea，policy，question，suggestion，wish，task，duty，job，purpose等或者主语是what引导的名词性从句时，后面可以用不
3、定式做表语，用以说明主语所包含内容。当不定式充当表语的时候，表示具体动作或是将来要发生的动作。如:1.My wish is to be a doctor.2.What she wants to do is to tell you a secret.3.His plan is to go abroad and continue his studies.PS:动名词和不定式同样都可以充当表语，两者的区别在于不定式表达是具体或是将来发生动作，而动名词则表示抽象的一般行为。e.g.1.His job is delivering the letters to their destinations.2.M
4、y job is to look after the sister when Mom is cooking.3.To do as an objectThe cat said“Remember not to take it next time!”(Tips:不定式否定为not to)a)可以直接用不定式作宾语的动词很多，如：agree，afford，tend，ask，decide，determine，expect，fail，hope，learn，intend，manage，offer，plan，promise，refuse，want，wishb)只有少数介词如but，except等后面可以跟不定
5、式作宾语。一般情况下作介词宾语的不定式都带to，但如果but或except所在句子里的谓语动词含有do，does，did时，通常省略to。e.g.We have no choice but to wait.=We can do nothing but wait.4.to do as an object complement You should get them to help you.(They will help you.)(常用谓语动词有：get，ask，force，order，tell，invite，allow，wish，want，like，expect，advise，beg，caus
6、e，persuade，teach，warn，hate，permit，forbid，encourage等。)通常这样的动词用在以下的结构里:verb+sb./sth.+to do sth.Tips:有些动词后面须接不带to的不定式做宾语补足语，常用的动词有:make，let，have，see；hear，watch，notice，feel；look at，listen to；help，observe 等，但是句子变成被动语态后，不定式成为句子的主语补足语，需带to。能带不定式作宾语的动词，其同源名词可以带不定式作定语。常见的有attempt，decision，promise，plan等。如：His
7、 eagerness to finish his homework was quite clear.常与不定式搭配的形容词，其同源名词一般可以用不定式作定语。常见的有ability，determination,anxiety，eagerness等。如：She was the only person to survive after the earthquake.5.to do as an attributive 序数词，形容词最高级或被only，last，next等修饰的名词可以用不定式作定语。Hes always the first to come and the last to leave
8、.(=The first comes and the last leaves.)(主谓关系)I have no time to listen to your excuse.(同位关系)She has a meeting to attend.(=attend a meeting)Theres nothing to worry about.(=worry about nothing)(动宾关系)so as to(不能放句首)，to，in order to作目的状语6.to do as an adverbial不定式可以作状语，表示目的、结果、原因、条件等。在soas to，suchas to，on
9、ly to 结构中不定式作结果状语，其中only to用于表示意想不到的结果。e.g.I am glad to meet you.形容词(glad，happy，lucky，fortunate，surprised，angry，anxious，ready，quick，slow，cruel，clever等)+不定式结构作原因状语 enough to，tooto结构e.g.The boy isnt old enough to go to school.=The boy is too young to go to school.7.作插入语，用来说明说话人的态度、看法、对整个句子进行解释，如：to be
10、 frank/honest(坦白地说)，to be sure(确实)，to make the matter worse(更糟糕的是)等。e.g.To tell you the truth,I hate you.Exercise 1(2015全国卷语法填空)When a new day breaks，the walls have given up their heat and are now cold enough (cool)the house during the hot day;at the same time,they warm up again for the night.2(2015广东高考语法填空)Since the plants took a while to grow,he started cutting down trees (sell)the wood.3(2014全国卷语法填空)I heard a passenger behind me shouting to the driver,but he refused (stop)until we reached the next stop.
