在国际贸易中，如信用证规定货物不得转船，卖方就必须取得承运人签发的( )后才能向银

下列哪项是早产儿视网膜病变的临床表现（）

A.急性期血管发生向无血管视网膜区过渡

B.病变早期在视网膜有血管区与无血管区之间出现分界线

C.分界处无增生性病变

D.视网膜血管走行正常

E.无牵拉性视网膜剥离

某公司员工小张在对自身进行风险管理时，发现有些风险属于发生损失频率高但造成损失程度低的风险，则小张应采用( )方法处理这种风险。

A．损失预防

B．损失抑制

C．风险转移

D．风险自留

评审员常住地发生省际变更的，应（）

A、向所在评价机构报告

B、向发证主管机关报告

C、申请换发资格证

D、由主管部门撤销资格证

电子政务建设的概念指将各级政府（部门）网络和应用系统连接起来，统一技术标准和规范，做到互联互通，从而实现构建统一的国家政务服务平台的目的。所以（）很关键。

A.统一标准与规范

B.操作系统

C.网站建设

In the two decades between 1910 and 1930, over ten percent of the Black population of the United States left the South, where the majority of the Black population had been located, and migrated to northern states, with the largest number moving, it is claimed, between 1016 and 1918. It has been frequently assumed, but not proved, that most of the migrants in what has come to be called the Great Migration came from rural areas and were motivated by two concurrent factors: the collapse of cotton industry following boll weevil infestation, which began in 1898, and increased demand in the North for labor following the cessation of European immigration caused by the outbreak of the First World War in 1914. This assumption has led to the conclusion that the migrants’ subsequent lack of economic mobility in the North is tied to rural background, a background that implies unfamiliarity with urban living and a lack of industrial skills.

But the question of who actually left the South has never been investigated in detail. Although numerous investigations document a flight from rural southern areas to southern cities prior to the Great Migration, no one has considered whether the same migrants then moved on to northern cities. In 1910 over 600,000 Black workers, or ten percent of the Black work force reported themselves to be engaged in "manufacturing and mechanical pursuits", the federal census category roughly including the entire industrial sector. The Great Migration could easily have been made up entirely of this group and their families. It is perhaps surprising to argue that an employed population could be tempted to move, but an explanation lies in the labor conditions then prevalent in the South.

About thirty-five percent of the urban Black population in the South was engaged in skilled trades. Some were from the old artisan class of slavery--blacksmiths, masons, carpenters--which had a monopoly of certain trades, but they were gradually being pushed out by competition, mechanization, and obsolescence. The remaining sixty-five percent, more recently urbanized, worked in newly developed industries--tobacco, lumber, coal and iron manufacture, and railroads. Wages in the South, however, were low, and Black workers were aware, through labor recruiters and the Black press, that they could earn more even as unskilled workers in the North than they could as artisans in the South. After the boll weevil infestation, urban Black workers faced competition from the continuing influx of both Black and White rural workers, who Were driven to undercut the wages formerly paid for industrial jobs. Thus, a move north would be seen as advantageous to a group that was already urbanized and steadily employed, and the easy conclusion tying their subsequent economic problems in the North to their rural backgrounds comes into question.

Notes: boll weevil infestation 棉铃虫蔓延。cessation 中止，停止。mason 泥瓦匠。recruiter 招募者。influx流入，涌入。

The author indicates explicitly that which of the following records has been a source of information in her investigation（）

A. United States Immigration Service reports from 1914 to 1930

B. The volume of cotton exports between 1898 and 1910

C. The federal census of 1910

D. Advertisements of labor recruiters appearing in southern newspapers after 1910