The way that primitive people invented fire is ( ).
A. make fire through drilling wood
B. make fire through striking stone
C. make fire through oil ignition
D. make fire through scraping
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The target organ for the toxicity of gelsemium elegan is ( ).
A. liver
B. kidney
C. nerves
D. brain
The poisoning cause of Itai-itai disease is ( ).
A. zinc
B. cadmium
C. selenium
D. lead
We must stregthen the confidence in the path, theories and system of socialism with Chinese characteristics, in the final analysis, we must insist on ( )
A. the confidence in the system
B. the confidence in the theories
C. the confidence in the culture
D. 无
有两个会话对一个有主键填空1]的表插入相同的主键值或惟一约束值,就会引起阻塞。最常用也是最有效的方法就是使用(______ )来生成主键/惟一列值。