1． “to” 是不定式符号还是介词，下列短语中的to 都是介词。
agree to object to close to , come to , lead to , refer to ,
equal to , familiar to , point to , thank to , devote to , next to , belong to , be used to , look forward to
2． 带to 还是不带to
I have no choice but to give in
I cannot do anything but give in
I saw him enter the classroom .
（ 但是： He was seen to enter the classroom .）
3． 动词不定式逻辑主语是由for 作为标记的。但是有时用of .
It’s necessary for you to study hard .（necessary 修饰 to study hard，表示学习努力是有必要的）
It’s foolish of him to do it .（foolish 修饰逻辑主语him）
good, kind , nice , wise ,clever , foolish , right , wrong , careful , careless , polite , …
want , hope , wish , like , begin , try , need , forget , agree , know , promise , teach , refuse , help , arrange , dare , decide , determine , fail , manage , offer , prepare , continue , ask , mean , choose , expect etc.
需要宾语补足语的动词不能用动词不定式直接做介词的宾语，而要用it做形式宾语。例如：通常不说We think to obey the laws is important . 而说We think it important to obey the laws .
5. 不定式作宾语补足语时省略to的情况：若不定式前的谓语动词是使役动词make，let，have（表示“让、使”）、感官动词see，watch，look at，observe， notice，hear，listen to， feel时，不定式符号to可以省略。这些动词亦可总结为口诀：“三使五看两听一感觉”。例如：
He saw the thief （to）steal a lady’s cellphone.
The thief was seen to steal a lady’s cellphone.
want to , wish to ,hope to , like to , hate to , plan to , try to , love to , have to , ought to , need to , used to , be able to
He has a lot of meeting to attend .
Please lend me something to write with .
He is looking for a room to live
He is looking for a room to live in .
He has no money and no place
to live ( in ) .
I think the best way to travel ( by ) is on foot .
There is no time to think ( about ) .
She is always the last ( person) to speak at the meeting .
----I’m going to the post office , for I have a letter to post . ( 逻辑主语是I )
-------Thank you. But I have no letters to be posted now ( 逻辑主语不是I )
He is lucky to get here on time .
happy , glad , delighted , pleased , sorry , eager , anxious . lucky , fortunate , proud , angry surprised , frightened , disappointed , ready , clever , foolish , worthy
He came to help me with my maths .
I hurried to get there only to find him out .
The book is too hard for the boy to read .
He is old enough to go to school .
8 . 不定式作补足语
I saw him play in the street just now .
see , feel , hear , listen to , look at , watch , let , have make, observe, notice
注: 当这些词为被动式时，不定式要带to , 如：
He was seen to play in the street just now.动名词
1．There’s no telling what will happen .
=It’s impossible to tell what will happen .
= No one can tell what will happen .
2．It’s no use talking with him .
It’s no good speaking to them like that .
3．There’s some difficulty ( in ) doing …
trouble , problem , fun , pleasure , a good time , a hard time注意以下几个问题：
forget to do … 忘记要做某事
forget doing… 忘记做过了某事
remember to do…记住要做某事
remember doing …记着曾做过某事
mean to do … 打算要做某事
mean doing … 意味着做了某事
regret to do …（do指代有限的几个词，如say、tell） 很抱歉要告诉你…
regret doing … 后悔做过某事
can’t help to do…不能帮助做某事
can’t help doing … 情不自禁做某事
try to do … 尽力去做某事
try doing 试着做某事
learn to do … 学着去做某事
learn doing … 学会做某事
stop to do … 停下来去做（另一件事）
stop doing … 停止做某事
go on to do … 接着做（另外一件事）
go on doing … 继续做某事
used to do … 过去做某事
be used to doing … 习惯做某事
动名词作定语表达 n+ for doing 的含义
现在分词作定语表达 n+which(who) be doing的含义
如：a sleeping car = a car for sleeping
a running horse = a horse which is running
前者是动名词 ， 后者是现在分词
又如： drinking water , walking stick running water , sleeping boy
例如：His coming made us very happy .
need doing , want doing , require doing
例如： This room needs painting . 这个房间需要粉刷。
admit , avoid , advise , consider , delay , deny , enjoy , escape , excuse , fancy , finish , complete , forbid , imagine , mind , miss , permit . practise , require , suggest , risk , keep, take to , look forward to , get down to , feel like , can’t help , can’t stand , be used to ,insist on , succeed in , set about, give up , include ,分词
1 The story is interesting . I’m interested in it .
2 . This is a moving film .
3. The secretary worked late into the night , preparing a long speech for the president .
4. Given more time , I’ll do it well .
When he passed the back of the street , he saw the thief stealing some money from the bank .
Do you know the woman talking to Tom ?
= Do you know the woman who is talking to Tom ?
The soldier wounded in the war has become a doctor.
= The soldier who was wounded in the war has become a doctor.
China is a developing country and America is a developed country.
The news sounds encouraging .
They got very excited .
The news is interesting . （表示主语的性质特征）
He is interested in the news . （表示主语的心理状态）
doing 作表语，主语与表语是主谓关系 ；done 作表语，主语与表语是动宾关系。
The blackboard was broken by Xiao Ming .（强调动作）
The blackboard is broken . You’d better have it repaired.（强调状态）
amused , injured , covered , known , dressed , lost , broken , gone , delighted, excited , pleased , satisfied , married , worried , surprised , interested , burnt , shut , crowded , wounded , drank , done
The situation in our country is encouraging . (表语)
The situation in our country is encouraging the people . ( 现在进行时)
My job is looking after the little baby . (动名词)
能回答how-question 的是现在分词，能回答what-question 的动名词，即不能回答how-question 也不能回答what-question 的是现在进行时。
例如： How is the situation in our country ? It is encouraging .
What is your job ? My job is looking after the little baby .
have something to do 有某事要做
have something done 使某事被做
have somebody do something 使某人做某事
have something doing 让某事一直做着
seat , prepare , hide , dress
如：I seated myself on the chair .
I was seated on the chair .
Having finished the homework , I went home . （ 时间）
Being a Party member , I should work hard . （原因）
Given more time ,I can do my work better . （ 条件 ）
He ran out of the classroom ,shouting at the boy. （ 伴随）
To get more knowledge , we must work harder and harder . ( 目的 )
He is old enough to join the army . （ 结果）
a running horse 现在分词 = a horse that is running
a fallen leaf 过去分词 = a leaf that has already fallen
a walking stick 动名词 = a stick for walking
something to do 不定式 = something that I should do
I have a problem to be discussed at the meeting . ( 将来)
The building being built on the river is the Science Museum . （正在进行）
The building completed three years ago is now in bad conditions . （ 过去）
Seeing from the hill , the city looks beautiful .( 错误 )
Seen from the hill , the city looks beautiful . （ 正确）
Seeing 与the city 不是主谓关系；seen 与city 是动宾关系