[思路分析]
首先要知道情态动词的特点：与实意动词一同构成谓语.
基于这一点来进行判断.
[解题过程]
用法如下：
一、 need的用法
1） need可用作实义动词,意为"需要；必要",后面可接名词、动名词或动词不定式等作宾语.注意"need doing"表示被动意义,相当于need to be done.例如：
I need a dictionary,so I need to go to the bookstore.我需要一本词典,因此我要去趟书店.
How often does your hair need washing（need to be washed）?你的头发需要多久洗一次?
2） need可用作情态动词,通常用于疑问句和否定句中,后接动词原形.这时need没有人称和数的变化,也没有时态的变化.例如：
It's only eight o'clock.Need you go so early?才八点.你需要去这么早吗?
You needn't tell him about it as I have told him.你不必跟他说那件事,我已经告诉他了.
3） needn't do与needn't have done的区别：
两者都表示"不必做.".但前者表示现在或将来不必做；而后者表示"过去（本来）不必做（而事实上已经做了）".例如：
You needn't carry the desks out of the classroom when you clean the classroom.你打扫教室时不必把桌子搬到教室外.
You needn't have bought such a big TV as it takes too much room.你本来不必买这么大的电视,它占据的空间太大了（而事实上已经买了）.
二、 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.