need的用法

Need 这个词可以当作情态动词和实义动词。
当它做情态动词时候,没有时态和人称的变化，其后面接动词原型，如你给的例句；I need do my homework now. 它的否定形式为 need not(或者needn't),表示为"没有必要",用于回答 must (必须)的提问.
当它做实义动词时候，有时态和人称的变化,其后面接不定式或者动名词，如你给的例句：I need to do my homework now, 它的否定形式为 don't need .如I常don't need to do my homework now.

A friend in need is a friend indeed.
患难之交是真朋友。
at (one's) need
在紧急时; 在困难时; 在危险时
be [stand] in need of ... ...
需要...
cryingneed
迫切的需要
do one's needs
[俚]解大[小]便
had need (to) do sth.
应该做某事
have need of [for]
需要做
have need to do sth.
必须做某事
If need be [were, require]
如果必要的话
in need
在危难中, 在危急中
in case [time] of need
在紧急的时候
N-makes the old wife trot.
[谚]急时老太婆也能跑。
need not have
[后接过去分词]本来不需要
What need(s)?
为什么要这样?

实意动词need可用于各种句子，而情态动词need只用于否定句和疑问句，不能用于肯定句。
所以，I need to wash the dishes.成立，而 I need wash the dishes不成立。

Need 这个词可以当作