require和need的区别是什么？

can 1.Used to indicate physical or mental ability:
能，会：用于表示身体或精神上的能力：
I can carry both suitcases. Can you remember the war?
我可以搬动两个箱子。你还能记得那场战争吗
2.Used to indicate possession of a specified power, right, or privilege:
拥有权利：用于表示拥有某种特殊权力、权利或特权，：
The President can veto congressional bills.
总统有权否决国会提案
3.Used to indicate possession of a specified capability or skill:
能力：用于表示具有某种能力或技能：
I can tune the harpsichord as well as play it.
我会弹奏大键琴，同样地，我也会给大键琴调音
4.Used to indicate possibility or probability:
可能：用于表示可能性或者或必然性：
I wonder if my long lost neighbor can still be alive. Such things can and do happen.
我怀疑我失踪已久的邻居是否还有可能活着。这样的事情可能而且确实发生了
5.Used to indicate that which is permitted, as by conscience or feelings:
允许：用于表示在意识和情感上得到允许的东西：
One can hardly blame you for being upset.
没有人会因为你受挫而责怪你
6.Used to indicate probability or possibility under the specified circumstances:
可能性：用于表示在特殊情形下的可能性或者可能的事：
They can hardly have intended to do that.
他们几乎不可能愿意做那事
7.Usage Problem Used to request or grant permission:
【用法疑难】 会：用于请求或给予允许：
Can I be excused?
我会得到原谅吗
may 1.To be allowed or permitted to:
许可：被允许或许可：
May I take a swim? Yes, you may.
我可以去游泳吗?是的，你可以
2.Used to indicate a certain measure of likelihood or possibility:
表可能性：用于表示可能或似乎也许的某种量度：
It may rain this afternoon.
今天下午可能会下雨
3.Used to express a desire or fervent wish:
希望：用于表达愿望、祝愿：
Long may he live!
愿他长寿!
4.Used to express contingency, purpose, or result in clauses introduced by that or so that :
能够：用于由that 或者 so that 引导的从句中，表示可能 、目的或结果：
expressing ideas so that the average person may understand.
把你的意思用一般人能听明白的话表达出来
5.To be obliged; must. Used in statutes, deeds, and other legal documents.See Usage Note at can 1
必须：有义务；必须。用于契约、证书或其他法令条款中参见 can1
must 1.To be obliged or required by morality, law, or custom:
必须：为道德良心、法律或者习惯所要求或强迫：
Citizens must register in order to vote.
为了进行选举，公民们必须登记
2.To be compelled, as by a physical necessity or requirement:
必须，必要：由于物质需要和要求而被迫：
Plants must have oxygen in order to live.
为了存活植物必须有氧气
3.Used to express a command or an admonition:
一定，必须：用来表示命令或者愿望：
You must not go there alone. You simply must be careful.
你一定不要单独去那里。你一定要小心
4.To be determined to; have as a fixed resolve:
一定：下决心一定要；坚持要：
If you must leave, do it quietly.
如果你一定要离开，那就悄悄地走
5.Used to indicate inevitability or certainty:
表示不可避免性或者可能性：
We all must die.
我们都会死
6.Used to indicate logical probability or presumptive certainty:
可能：用来表示逻辑推断的可能性或假定的必然性：
If the lights were on, they must have been at home.
如果灯亮着，那么他们一定在家
n.（名词）
1.Something that is absolutely required or indispensable:
一定，绝对：绝对必要或不可避免的应当去做之事：
Promptness on the job is a must. Comfortable shoes are a must when taking a walking tour of Wales.
工作上准时是绝对必要的。步行去威尔士旅行时舒服的鞋是绝对必要的物品
n.attributive.（定语名词）
1.Often used to modify another noun:
常用来修饰另一个名词：
a new book that is must reading; a list of must legislation for the session.
一本不可不读的新书；开庭不可缺少的立法一览表
need 1.A lack of something required or desirable:
需要：对想要或期望的事物的缺乏：
crops in need of water; a need for affection.
需要水的庄稼；对感情的需要
2.Something required or wanted; a requisite:
必需品：要求或需要的事物；需要物：
Our needs are modest.
我们的必需品是谦虚
3.Necessity; obligation:
必要；义务：
There is no need for you to go.
你没有必要去
4.A condition of poverty or misfortune:
贫困：贫穷或不幸的状况：
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）
1.To be under the necessity of or the obligation to:
必须要：必须要，有义务要：
They need not come.
他们不必来
v.tr.（及物动词）
1.To have need of; require:
需要；想要：
The family needs money.
这个家庭需要钱
现在完成时和现在完成进行时的区别和用法
http://www.lesun.org/english/html/2005-04/3524.htm