用作情态动词时:dare/dare not do sth.
用作实意动词：don't dare to do sth
I dare not ask him this question.
I don't dare to ask him this question.
我不敢问他这个问题。
dare的用法
1） dare用作实义动词，此时其后的动词不定式可带to也可不带to，且dare有人称和数以及时态的变化。例如：
I dare to jump down from the top of the wall. 我敢从那墙头上跳下来。
She doesn\'t dare (to) meet her teacher\'s eyes. 她不敢与老师对视。
2） dare用作情态动词，后跟动词原形，主要用于疑问句、否定句和条件句中。例如：
How dare she do things like that to me? 她怎么敢对我做那种事?
-Dare you catch the mouse? 你敢去抓那只老鼠吗？
-I daren\'t do that. 我不敢抓。
If you dare say that to our teacher, I would vote for you. 如果你敢向我们的老师说那件事，我就投你一票。
dare
v.（动词）
dared， dar.ing， dares
v.t（及物动词）
To have the courage required for:
敢：有要求达到的胆量：
The gymnast dared a breathtakingly difficult move.
这位体操选手敢于做惊险的高难度动作
To challenge (someone) to do something requiring boldness:
挑衅：挑起（某人）去做要求勇敢的事：
They dared me to dive off the high board.
他们挑衅我从高台上跳下水中
To confront or oppose boldly; defy.See Synonyms at defy
向…挑战：勇敢地面对或反对；公然反抗参见 defy
v.intr.（不及物动词）
To be courageous or bold enough to do or try something:
勇于，胆敢：有足够的勇气或胆量做或试着做某事：
Go ahead and dive if you dare.
如果你敢，尽管跳下水去
v.aux.（助动词）
To be courageous or bold enough to:
胆敢：有足够的勇气和胆量：
I dare not say. How dare she go?
我不敢说。她怎么敢去呢?
n.（名词）
An act of daring; a challenge.
挑衅的行为，挑战
Depending on its sense, the verb dare sometimes behaves like an auxiliary verb (such as can or may ) and sometimes like a main verb (such as want or try ). When used as an auxiliary verb, dare does not agree with its subject:
从意义上来说，动词dare 有时相当于助动词（如 can能 或 may可能 )， 有时相当于实义动词 （如want想 或 try试着 )。 当用作助动词时，dare 不和主语一致：
Let him say that if he dare.
如果他敢的话让他说，
It also does not combine with do in questions, negations, or certain other constructions:
它也在疑问句、否定句和其他某些结构中，不需和do 连用：
Dare we tell her the truth?
我们敢告诉她实情吗?
I dare not mention their names.
我不敢提他们的名字。
Finally, it does not take to before the complement verb that follows it:
最后，在紧跟其后的辅助动词前不用带上to ：
If you dare breathe a word about it I'll never speak to you again.
如果你敢说出去一个字，就再不和你说话。
When used as a main verb, dare does agree with its subject (
当用作实义动词时，dare 一定要和主语一致(
If he dares to show up at her house I'll be surprised),
如果他敢出现在她的房子里，我会感到吃惊)，
and it does combine with do (
它必须和do 连用(
Did anyone dare to admit it?).
有人敢于承认吗?)。
It may optionally take to before the verb following it:
有可能选择性地在紧跟其后的动词前加to ：
No one dares (or dares to ) speak freely about the political situation.
没有人敢（或 dares to ) 自由地谈论政治形式 。
The auxiliary forms are used primarily in present tense questions, negations, imperatives, and conditional clauses. These forms differ subtly in meaning from the main verb forms in that they emphasize the attitude or involvement of the speakerwhile the main verb forms present a more objective situation. Thus How dare she take the exam without ever once coming to class? expresses indignation at the student's action, whereas How did she dare to take the exam without ever once coming to class? is a genuine request for information. When dare is used as a transitive verb meaning “challenge,” only main verb forms are possible and to is required:
助动词形式主要用于一般现在时疑问句、否定句、祈使句和条件从句中。这些形式和实义动词形式的意思有细微的差别，即他们强调说话者的态度和参与，而实义动词形式给出一个较客观的形势。因此她怎么敢从未上过课就参加考试呢? 表示对该学生行为的愤怒， 然而她从未上过课怎么敢参加考试呢? 是一真实的信息需求， 当dare 用作及物动词意指“挑战”时， 只能是实义动词形式而且要接to ：
Anyone who dares (not dare ) him to attempt (not just attempt ) it will be sorry.
任何敢于（不是 dare ) （不仅仅是 attempt ) 挑衅他去做的人会遗憾的