为什么need（实意动词）是加to do形式不是doing?

Need to do something ,
Need to be done(Need doing)
当主语是人或者其它施力物体时用Need to do something
Eg ,you need to clean yourself now !
当主语是受体是用Need to be done(need doing）
Eg ,
You car looks so dirty ,it needs washing(You need to wash your car)
Dare 和Need 不一样
Dare 可以做情态动词,这时后面敢原型
不做情态动词时有Dare to do something有胆量做Sth
Dare sb to do sth挑衅Sb做Sth