情态动词dare通常不用于肯定句dare

可以Depending on its sense,the verbdare sometimes behaves like an auxiliary verb (such as can or may ) and sometimes like a main verb (such aswant 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 withdo 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 taketo 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 withdo (
它必须和do 连用(
Did anyone dare to admit it?).
有人敢于承认吗?).
It may optionally taketo 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 ) *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 formsin that they emphasize the attitude or involvement of the speakerwhile the main verb forms present a more objective situation.ThusHow dare she take the exam without ever once coming to class?expresses indignation at the student's action,whereasHow did she dare to take the exam without ever once coming to class?is a genuine request for information.Whendare is used as a transitive verb meaning “challenge,” only main verb forms are possible andto 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