不带to的动词不定式通常有下面十八种情况
动词不定式通常带有符号to，叫做带to的动词不定式(infinitive with"to")，动词不定式有时不带符号to，叫做不带to的动词不定式
不带to的动词不定式通常有下面十八种情况
一、与助动词do连用构成谓语动词的否定、疑问和强调形式。
(2)Does she work here？
(4)Did they
(6)They did come
二、与情态动词连用构成复合谓语
(3)Dare he swim across the river?
(4)We must work,and
(5)Could you do something for me?
(6)You shall go
(7)He might be working in the office now.
(8)I don't think you need have come yesterday.
(9)They should be here by now.
(10)If you will go into the fields and turn over a few big stones,you are sure to uncover a city of
但与情态动词ought(to)连用时通常带to，和used(to)连用时必须带
三、在表示感觉的动词如：see,look.at,watch,hear,listen
to,feel,notice,observe,perceive(觉察，看见),behold（书面用语“见到”）等后用作宾语补足语的动
词不定。
(2)He looked at the children walk up the hill.
(4)I heard her
(6)I felt the
(9)I did not perceive anyone come in.
(10)He beheld
但除notice,watch不用被动语态外，上述动词变成被动语态时，其后的动词不定式就不省to
(2)She was
四、使役动词make,let,have,bid, leave(=let)后作宾语补足语的动词不定式不带
(4)Bid him go home.
动词have通常不用于被动语态，make和bid可用于被动语态，let偶尔也可用于被动态，用作主语补足语的动词不定式通常带to，但在make和let后有时可以不带to
(2)He was made(t
(3)The child
五、never与know连用其后作宾语补足语的动词不定式可省to，其时态多为完成时态。
(1)I never knew him act without thinking.
(2)I've never known it snow in July before.
(3)I had never known
有时ever与known连用也有上述用法。
(1)Have you ever known me tell a
六、在find后作宾语补定语的动词不定式有时可以省to，但如动词为be，那么一般不省to，要省一起省略
(2)I find the
(3)I found this to be true in all the cities.
(4)We found him (to be) honest/dishonest.
七、在cannot but,cannot help but,can not choose but, had better(best),would(had)
rather(sooner)…than…, would as
soon…as…后的动词不定一般不带to
(4)I had better leave now,or I'll be late.
(6)I would rather go mountain—
(7)My aunt invited me to the movies,but I said I had rather go on a picnic with the girls.
(9)He would sooner resign than take part in such dishonest business
八、在but(=except),besides,than后的动词不定式一般要带to，但如果其前有作谓语的实义动词do，则不定式不带
(1)The soldier has no choice but to obey.
(2)He did not have any choice but to obey.
(4)The children found there was nothing they could do with their money,except spend it on
sweets.
(5)There seemed nothing else to do but(to)send for a doctor.(but前的实义动词do不作谓语，but 后的不定式可带to，也可不带
九、不定式作表语时，如主语部分含有实义动词do，且句子的时态为一般现在时或一般过去时(多为is或was)，不定式可以带to也可不带to
(1)What we must do now is(to) find anther person to h
如句子的动词时态不是一般现在时或一般过去时，作表语的动词不定式一般要带
十、rather than位于句首时，其后用不带to的不定式，但rather
than在句中时，其后的动词不定式可以带to，也可以不带
十一、在动词help后作宾语补足语的动词不定式可以带to，也可以不带，在英国英语中，多用不带to的不定式，但在英国英语中，help+宾语+不定式结构中，用不带to的不定式表示主语直接参与不定式的表
示的动作，用带to的不定式表示主语没有直接参与不定式的表示的动作。
(3)This kind of soap
但在被动语态中，help后的不定式要带
在help(to) do sth不定式符号to可省略。
He helped(to) repair the
十二、两个或两个以上的动词不定式并列在一起时，第一个不定式带to，后面的不定式一般省去但如果是在对照场合，则不省去
(1)It is better to la
(2)The purpose of new technologies is to make life easier,not to
十三、than连接两个动词不定式没有对比关系时，后一个不定式可以省
(1)You might do worse than(to) do as he does.
(2)I cannot do better than(t
下面句子中than连接的不是两个动词不定式than后的动词不定式通常要带
(1)I know better than to believe him.
下句中的more than(=only)可以看成复合副词，后面的动词不定式不带to
十四、在why,why not后的不定式不带to
(2)Why not join
十五、实义动词dare在现代英语口语中，其所在的否定句或疑问句中，它后的动词不定式可省to，尤其在一般过去时中
(2)We do not dare
(4)Did he dare
十六、在口语中，特别是在美国，祈使语气谓语动词和构成谓语的不定式go后面的不定式往往不带to 这种用法在英国口语中比较少见，一般在动词go后用连词
(2)I'll go and see
十七、在"will you please…?"和would you please…？句型中，要用不带to的不定式。
(2)Will you ple
十八、Better+动原(口语中用
(2)Better go at once.。