NOTE ON USAGE 用法:
Note that principle is a noun relating to rules of behaviour 注意:
principle是名词, 指行为的规范:
She leads her life according to Christian principles. 她以基督教教义作为生活的准则. Principal is a (rather formal) adjective meaning `main' or `most important' *principal是（较文的）形容词, 意为｀主要的＇或｀最重要的＇:
My principal concern is my family's welfare. 我至为关心的是我一家的幸福. *
the principal objections to the proposal 对该项建议的主要反对意见. As a noun it is used for the director of certain educational institutions (usually in further education) 该词若用作名词则指某些教育机构（通常属继续教育性质）之领导人:
The principal and the vice-principal of the college both attended the meeting. 学院的正副院长均出席了会议. principle 2
[/ˈprɪnsəpl; ˋprɪnsəpl/] n用法:
1 [C] basic general truth that underlies sth (eg a subject or a system of morality) 原理; 原则:
a textbook which teaches the basic principles of geometry 讲解几何学基本原理的教科书 *
the principle of equality of opportunity for all 人人机会均等的原则 *
Discussing all these details will get us nowhere:
we must get back to first principles. 讨论这些枝节问题是毫无用处的, 我们必须回到基本原则上来. 用法:
2
(a) [C usu pl 通常作复数] guiding rule for personal behaviour （行为的）准则, 规范:
principles of conduct 行为的准则 *
live according to/up to one's principles 按自己的标准行事 *
She seems to have no principles at all (ie behaves immorally) when it is a question of making money. 一碰到赚钱的事, 她就好像完全不顾自己的人格了. *
It would be against my principles to lie to you. 对你说假话是违背我的行为准则的.
(b) [U] these rules 操守; 道义; 为人之道:
a woman of (high) principle 操守好的女人 *
He is quite without principle, ie behaves immorally. 他完全没有道德观念（做的事不道德）. *
It is a matter of principle with her to answer her children's questions honestly. 如实地答覆孩子们的询问对她来说是关系到做人的大问题. 用法:
3 [sing] general or scientific law shown in the way a thing works, or used as the basis for constructing a machine, etc （事物的）工作原理; （机器等的）构造原理:
These machines both work on the same principle. 这两台机器的工作原理是相同的. *
The system works on the principle that heat rises. 该项装置是按照热力上升的原理运转的. =>Usage at principal 用法见principal. 用法:
4 (idm 习语) in principle (a) as far as basic principles are concerned 原则上:
There's no reason in principle why people couldn't travel to Mars, ie It is possible, though it has not yet been done. 从理论上讲, 没有理由认为人不能到火星上去（尽管目前还做不到, 但却是可能的）.
(b) in general but not in detail大体上; 基本上:
They have agreed to the proposal inprinciple but we still have to negotiate the terms. 他们基本上同意了那项提议, 但我们仍须商定条件. on principle because of one's (moral) principles or a fixed belief 依据自己的（道德）原则或所确定的信念:
Many people are opposed to the sale of arms on principle. 许多人根据自己的是非观反对出售武器. |