( )是目前描述操作系统十分有效的高级设计语言，具有描述力强、灵活、方便等特点。A．

有人把分化细胞中表达的基因形象地分为“管家基因”和“奢侈基因”，“管家基因”在所有细胞中表达，是维持细胞基本生命活动所必需的；而“奢侈基因”只在特定组织细胞中表达，下列属于“奢侈基因”表达产物的是[ ]

A．ATP水解酶

B．核糖体蛋白

C．膜蛋白

D．血红蛋白

To my joy,everyone agreed with my proposals at the meeting.

2009年3月，为提高本省房地产中介服务水平，规范房地产市场，A省房地产估价师与房地产经纪人学会(以下简称A省学会)研究决定：一是从源头抓起，加强房地产经纪人的考试、注册和管理工作；二是积极做好房地产经纪人的交流协作、培训等继续教育工作。
A省B市C房地产经纪公司为落实A省学会的决定，组织本公司张某、李某参加培训，并参加2009年度的全国房地产经纪人考试；张某大专学历，李某大学本科学历。两人在一个考试年度内通过了经纪人考试并于第二年参加经纪人注册，注册后张某在执业过程中由于同时在其他经纪机构兼职执业被学会吊销了执业资格证书。

张某和李某经纪人注册的有效期是：( )。

A．1

B．3

C．4

D．6

Du Bois was a sociological and educational pioneer who challenged the established system of education that tended to restrict rather than to advance the progress of black Americans. He challenged what is called the “Tuskegee machine” of Booker T. Washington, the leading educational spokesperson of the blacks in the U. S. . As a sociologist and historian, Du Bois called for a more determined and activist leadership than Washington provided.

Unlike Washington, whose roots were in southern black agriculture, Du Bois’s career spanned both sides of the Mason-Dixon Line. He was a native of Massachusetts, received his undergraduate education from Fisk University in Nashville, did his graduate study at Harvard University, and directed the Atlanta University Studies of Black American Life in the South. Du Bois approached the problem of racial relations in the United States from two dimensions: as a scholarly researcher and as an activist for civil rights. Among his works was the famous empirical sociological study, The Philadelphia Negro: A Social Study, in which he examined that city’s black population and made recommendations for the school system. Du Bois’s Philadelphia study was the pioneer work on urban blacks in America.

Du Bois had a long and active career as a leader in the civil rights movement. He helped to organize the Niagara Movement in 1905, which led to the National Association for the Advancement of Colored People (NAACP), established in 1909. From 1910 until 1934, Du Bois edited The Crisis, the major journal of the NAACP. In terms of its educational policy, the NAACP position was that all American children and youth should have genuine equality of educational opportunity. This policy, which Du Bois helped to formulate, stressed the following themes: (1) public schooling should be free and compulsory for all American children; (2) secondary schooling should be provided for all youth; (3) higher education should not be monopolized by any special class or race.

As a leader in education, Du Bois challenged not only the tradition of racial segregation in the schools but also the accommodationist ideology of Booker T. Washington. The major difference between the two men was that Washington sought change that was evolutionary in nature and did not upset the social order, whereas Du Bois demanded immediate change. Du Bois believed in educated leadership for blacks, and he developed a concept referred to as the “talented tenth”, according to which 10 percent of the black population would receive a traditional college education in preparation for leadership.

Compared with Booker T. Washington, Du Bois’s stance was（）

A. less popular

B. more radical

C. less aggressive

D. more conservative

列车自动制动机的试验形式规定了哪几种？