He daren't go there because it is very dangerous.他不敢去那兒，因?yàn)槟莾汉芪ｋU(xiǎn)。2．dare用作實(shí)義動(dòng)詞時(shí)，有時(shí)態(tài)和人稱(chēng)的變化，用do, does或did來(lái)構(gòu)成否定句或疑問(wèn)句。She didn't dare to say a word, did she?她一句話(huà)也不敢說(shuō)，是嗎？六、have to的用法have to意為“不得不”，有時(shí)態(tài)、人稱(chēng)和數(shù)的變化，其否定形式為don't/doesn't/didn't have to。It's too late. I have to go home now.天色太晚了，我現(xiàn)在得回家了。You don't have to finish the work now.你沒(méi)有必要現(xiàn)在完成這項(xiàng)工作?！军c(diǎn)津】 have to和must的區(qū)別：have to表示一種客觀(guān)的需要，而must表示一種主觀(guān)的需要。此外，must還表示“偏要”“非得”的意思。I have to attend an important meeting this afternoon.今天下午我不得不參加一個(gè)重要的會(huì)議。I must clean the room because there are too dirty.因?yàn)樘K了，我必須要打掃房間。七、had better的用法had better意為“最好；應(yīng)該”，后跟動(dòng)詞原形，常用來(lái)提出建議，或表示迫切的希望、警告等，語(yǔ)氣較強(qiáng)。其中動(dòng)詞had沒(méi)有人稱(chēng)或數(shù)的變化。had better的簡(jiǎn)略式為：'d better，否定式為：had better not。She'd better get here soon or she'll miss the opening ceremony.她最好快點(diǎn)到這兒來(lái)，否則她會(huì)錯(cuò)過(guò)開(kāi)幕式的。