数据库、数据库管理系统和数据库系统是3个不同的概念,其中数据库系统
强调的是()。
A 数据
B 系统软件
C 运行环境
D 数据结构
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混凝土的养护是在混凝土浇筑完毕后6h内进行,养护时间通常为14～28d.混凝土浇筑后应对养护的时间进行检查落实。()
安装在卫生间及厨房的管道套管,其顶部应高出装饰地面()mm.
By citing the examples of Obamas re-election and inaugural address, the author intends to
A. analyzing data from sources like Twitter can be an accurate substitute for more traditional research methods
B. Pew Research Center"s study on Twitter users" online musings and their poll respondents is questionable
C. Tweets are inconsistent in how they match up with polling data
D. Twitter users usually hold mutually contradictory political beliefs
If properly managed, trophy hunting______.
A. may help protect wildlife and habitats
B. can replace hunting for food and for sport
C. becomes less barbaric than hunting for sport
D. will provide foreign operators with more benefits
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