两轮节圆上的模数和压力角分别相等

两轮的法向齿距应相等

两轮的基圆齿距应相等

两轮的分度圆模数和压力角分别相等

the focus on life

the emphasis of unyielding spirit

the significance of action

the prominence of dignity

Jane Eyre

Pride and Prejudice

Wuthering Heights

Old Man and the sea

读者遗失图书，按所借的书籍自行购买赔偿

确实无法购买原书籍赔偿的，经申请后可购买等值书籍赔偿

读者遗失图书的，须在应还日期之前向图书馆报告，超期后报告的，同时按照超期使用文献资源催还和处理标准处理

contrasting the meanings of two related words

giving examples of different kinds of education

listing and discussing several educational problems

providing facts to support an argument Passage 2 Education is one of the key words of our time. A man, without an education, many of us believe, is an unfortunate victim of unfortunate circumstances deprived of one of the greatest twentieth century opportunities. Conceived of the importance of education, modern states “invest" in institutions of learning to get back “interest" in the form of a large group of enlightened young men and women who are potential leaders. Education, with its cycles of instruction so carefully worked out, is punctuated by textbooks-- those purchasable wells of wisdom- -what would civilization be like without its benefits? So much is certain: That we would have doctors and preachers, lawyers and defendants, marriages and births; but our spiritual outlook would be different. We would lay less stress on “facts and figures" and more on a good memory, on applied psychology, and on the capacity of a man to get along with his fellow citizens. If our educational system were fashioned after its bookless past we would have the most democratic form of “college" imaginable. Among the people whom we like to call savages all knowledge inherited by tradition is shared by all; it is taught to every member of the tribe so that in this respect everybody is equally equipped for life. It is ideal condition of the “equal start” which only our most progressive forms of modern education try to reach again. In primitive cultures the obligation to seek and to receive the traditional instruction is binding to all. There are no “lliterate'- -if the term can be applied to peoples without a script-- while our own compulsory school attendance became law in Germany in 1642, in France in 1806, and in England in 1976, and is still nonexistent in a number of “civilized" nations. This shows how long it was before we considered it necessary to make sure that all our children could share in the knowledge accumulated by the “happy few" during the past centuries. Education in the wildness is not a matter of monetary means. All are entitled to an equal start. There is none of the hurry which, in our society, often hampers the full development of a growing personality. There, a child grows up under the ever-present attention of his parents; therefore the jungles and the savages know of no “juvenile delinquency". No necessity of making a living away from home results in neglect of children, and no father is confronted with his inability to “buy” an education for his child.

模数、压力角均相等

仅模数相等

仅压力角相等

A 是基极， B 是集电极， C 是发射极， NPN 型

A 是集电极， B 是基极， C 是发射极， NPN 型

A 是发射极， B 是集电极， C 是基极， PNP 型

A 是基极， B 是发射极， C 是集电极， PNP 型