下列关于关系模型完整性约束的叙述不正确的是A．对关系属性取值是否为空值约束属于域完整

一位同学不慎被小刀划破手指，流出了血，小刀至少划到了皮肤的               [ ]

A．表皮角质层     

B．表皮生发层    

C．真皮     

D．皮下组织

Many lifestyle patterns do such______ great harm to health that they actually speed up_______

weakening of the human body.     [ ]

A. a;/      

B. /;the    

C. a;the    

D. /;/

我国低碳经济发展应遵循路径，不正确的是()

A.能源技术进步与绿色技术创新相结合

B.碳排放权交易制度与绿色技术创新相结合 

C.仅发展经济

D.绿色技术的创新和发展

随机接入失败的可能原因是什么（）。

A.超出了MAXTA

B.超出了TALIM

C.SDCCH拥塞

D.以上都有

E.以上都不是

Politician: Fewer people are entering the labor market now than previously. If the economy grows, the demand for motivated and educated people will far outstrip the supply. Some companies have already started to respond to this labor-market situation by finding better ways to keep their current employees. Their concern is a sure indicator that the economy is growing.
Which of the following is the best criticism of the politician’s reasoning

A．The fact that companies are making prudent preparations for a possible future development does not mean that this development is already taking place.

B．The fact that some companies now try harder to keep their employees does not mean that they used to be indifferent to employee morale.

C．The fact that demand will outstrip supply does not mean that there will be no supply at all.

D．The fact that the number of new entrants into the labor market is declining does not mean that the number of new entrants is lower than it has ever been.

E．(E) The fact that current employees have become more valuable to some companies does not mean that those employees will do their jobs better than they used to.