need

lack, need, want, require

need(普通动词), need(情态动词)

• the pen needs mending.
  这支钢笔需要修理。
• does she need to go to the club?
  她必须去俱乐部吗？
• she does not need to go there at present.
  现在她不必去那里。

• need she go now?
  她必须现在去吗？
• she need not come to school at present.
  她现在不必来学校。
• 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）

名词 need:

1. a condition requiring relief
   同义词：demand
2. anything that is necessary but lacking
   同义词：want
3. the psychological feature that arouses an organism to action toward a desired goal; the reason for the action; that which gives purpose and direction to behavior
   同义词：motivation, motive
4. a state of extreme poverty or destitution
   同义词：indigence, penury, pauperism, pauperization

动词 need:

1. require as useful, just, or proper
   同义词：necessitate, ask, postulate, require, take, involve, call for, demand
2. have need of
   同义词：want, require
3. have or feel a need for

1. I feel a need to talk to you about it.
   我觉得有必要跟你谈谈那件事。
2. We are collecting money for children in need.
   我们在为贫困儿童募捐。
3. You needn't talk so loud.
   你说话的声音用不着那么大。
4. The doctor told me I was in need of a good rest.
   医生对我说，我需要好好休息。
5. If I need you to come and help I'll call.
   如果我需要你来帮忙，我会打电话的。

need

n.（名词）
A lack of something required or desirable:
需要：对想要或期望的事物的缺乏：
例句：
crops in need of water; a need for affection.
需要水的庄稼；对感情的需要

Something required or wanted; a requisite:
必需品：要求或需要的事物；需要物：
例句：
Our needs are modest.
我们的必需品是谦虚

Necessity; obligation:
必要；义务：
例句：
There is no need for you to go.
你没有必要去

A condition of poverty or misfortune:
贫困：贫穷或不幸的状况：
例句：
The family is in dire need.
这个家庭极为贫困

v.（动词）
need.ed,need.ing,needs
aux.（助词）
To be under the necessity of or the obligation to:
必须要：必须要，有义务要：
例句：
They need not come.
他们不必来

v.tr.（及物动词）
To have need of; require:
需要；想要：
例句：
The family needs money.
这个家庭需要钱

v.intr.（不及物动词）
To be in need or want.
需要，想要
To be necessary.
有必要

来源：
Middle English nede
中古英语 nede
from Old English nôod, nôd [distress, necessity]
源自 古英语 nôod, nôd [穷困，贫困]

<参考词汇><同义词>need,necessity,exigency,requisiteThese nouns denote a condition in which something essential is required or wanted; they also refer to that which is required or wanted.
这些名词都指处于对必需品的要求和需求的一种状况；它们也指需要的或要求的东西。
Need is the most general:
Need 最普遍：
例句：
There`s no need to be concerned.
没必要担忧。

例句：
She is serene and contented;
她很安详、平静；

例句：
her emotional and spiritual needs are being met.
她感情和精神上的需要都得到了满足。

Necessity more strongly thanneed suggests urgency, inevitability, or unavoidable obligation:
Necessity 比need 更强， 用来指紧迫的、不可避免的或不可躲避的义务：
例句：
.I think the necessity of being ready increases.—Look to it. (Abraham Lincoln).
.我认为做好准备的 紧迫性增加了。——注意. （亚伯拉罕·林肯）。

例句：
.The rehabilitation of the cabin became a necessity. (Bret Harte).
.小屋的重新修建已是不可避免的了. （布雷特·哈特）。

Exigency implies acute urgency,especially that arising from conditions or circumstances such as those of an emergency:
Exigency 指非常紧迫，尤指产生于类似紧急事件的条件或环境：
例句：
.No . . . more pernicious [doctrine] was ever invented . . . than that any of [the Constitution`s] provisions can be suspended during any of the great exigencies of government. (David Davis)
.没有…曾经创造的 能比在一次政府的危急关头对 条款的取消更为有害的. （大卫·戴维斯）。

Requisite applies to something indispensable:
Requisite 指不可缺少的事物：
例句：
.a place where the three grand requisites of water, fuel and fodder were to be obtained. (James Fenimore Cooper).See also Synonyms at lack
.三种主要必需品，水、燃料和草料都具备的地方. （吉姆斯·费尼莫尔·库珀）参见同义词 lack

Depending on the sense,the verbneed behaves sometimes like an auxiliary verb (such as can or may ) and sometimes like a main verb (such aswant or try ). When used as a main verb,need agrees with its subject, takesto before the verb following it, and combines withdo in questions, negations, and certain other constructions:
根据语义，动词need 有时当作助动词来使用（如 can 或 may )， 有时象实义动词（如want 或 try )。 当用作实义动词时，need 和主语一致， 把to 放在其后面动词的前面， 在疑问句、否定句或某些特定的造句法上和do 连用：
例句：
He needs to go.
他想走。

例句：
Does he need to go so soonô
他这么快就要走吗ô

例句：
He doesn`t need to go.
他不需要走。

When used as an auxiliary verb,need does not agree with its subject, does not taketo before the verb following it, and does not combine withdo :
当用作助动词时，need 不用和主语一致， 不用把to 放在其后动词的前面， 并且不用和do 连用：
例句：
He needn`t go.
他不必走。

例句：
Need he go so soonô
他这么快就要走吗ô

The auxiliary forms ofneed are used primarily in present-tense questions, negations, and conditional clauses. They differ subtly in meaning from the main verb forms in that they always refer to an externally imposed obligation.Hence one might sayYou needn`t (or less formally, don`t need to ) fill out both forms, but where the sense of necessity is internal to the subject,only the main verb can be used:
Need 的助动词形式主要用于现在时态的疑问句、否定句和条件句中。 它们在意思上和用作实义动词的形式有细微的区别，它们总指外部加强的压力。因此我们可以说你没必要 （或不太正规的 don`t need to ) 填两份表格 ， 但是对于物体来说需要的意思是内在的，所以只能用实义动词：
例句：
I don`t need to (not needn`t ) be told how to manage my own affairs.
我不需要（而不是 needn`t ) 被告诉怎知管理自己的事情 。

Note also that the use ofneed as an auxiliary is often accompanied by a presupposition that the activity in question has in fact been performed.The boys needn`t have spoken frankly implies that they did in fact speak frankly, whereas the sentenceThe boys did not need to speak frankly does not; only the latter could be followed by a clauselikethey conveyed their meanings by indirection.
还需注意need 用作助动词时经常伴随一个先决条件， 质问的动作事实上已经完成了。那些男孩们本来不需要坦诚相告的 意味着他们事实上已经坦率地说了， 然而这个句子男孩们不需要坦诚地说话 就没有这个意思； 只有后者可以在其后跟这样一个句子，如他们间接地表达他们的意思