这一对词的用法和区别与dare大体相同。need的意义是"需要"、"必须",既可用作普通动词,又可用作情态动词。
作普通动词时,它有各种时态形式的变化;第三人称单数现在时要加-s;与带to的不定式连用。如:
Does she need to go to the club?
She does not need to go there at present.
作情态动词时,没有过去形式;第三人称单数现在时不加-s;不用在肯定句里,只用于疑问句和否定句;与不带to的不定式连用;如:
She need not come to school at present.
Mary need not have done it.
玛丽本来不必去做那件事。(言外之意是:她已经做了)
从上例可见,当need not之后接完成体的不定式时,表示"已做了原来无需做的行为"之意。因此,现在我们可以正确区分下列两句的不同涵义:
He didn't need to come to school.(没有来)
He need not have come to school.(已来过)
除作动词外,need还可以用作名词。如:
There is no need to hurry.
The need for more cooperation is felt.
They are in need of relief.
作名词时,need还可以表示"逆境"、"穷困"之意。如:
Don't fail a person in his need.