在数据库系统的三级组织结构中,DBA视图是(),系统程序员视图是(),用户视图是()。
参考答案:概念模式;内模式;外模式
短文填空。
"Tell me what you are 1. (go) to do on Sunday morning, Jim, "Mr. Wang asks. "I am going to
see a new film. It's an English film about the life of the 2. (student) in America. Bill tells me it's
very 3. (interest)" "After 4. (see) the film, what are you going to do?" Mr. Wang wants to
know. "I am going to read Chinese," Jim says. "Do you like it?" asks Mr. Wang." Chinese is not easy for
me, but I like it very much. I am going to work hard at it. After lunch I am going to have English and
other subjects. I think I can do 5. (good) than before."
在一项有关吸烟与肺癌的病例对照研究中,资料分析显示:吸烟与肺癌的关联程度的χ2检验结果P<0.05,OR=4.7,说明()。
A.病例组的肺癌患病率明显高于对照组
B.病例组的肺癌发病率明显高于对照组
C.病例组患肺癌的可能性明显高于对照组
D.对照组患肺癌的可能性明显高于病粒组
E.吸烟者患肺癌的可能性明显高于不吸烟者