need 和dare 既可作情态动词,又可以作为一般实意动词来用.区别在于作为实意动词时它们有人称、时态和数的变化,否定和疑问时要加助动词；作为情态动词时不论什么人称和时态时都用其原形不变化.同时,作为实意动词,其后要接to do ... 例如：I need to have a rest. She doesn't dare to go there. Did you need to see him?
而情态动词后只能接原形动词：How dare she do that?You need come on time. She dare not go there.