问题 单项选择题

下面列出的条目中,哪一条是数据仓库的基本特征
Ⅰ.数据仓库是面向主题的 Ⅱ.数据仓库的数据是集成的
Ⅲ.数据仓库的数据是相对稳定的 Ⅳ.数据仓库的数据是反映历史变化的

A.Ⅰ,Ⅱ和Ⅲ

B.Ⅰ,Ⅱ和Ⅳ

C.Ⅱ,Ⅲ和Ⅳ

D.都是

答案

参考答案:D

解析: 数据仓库的特点为:数据仓库是面向主题的;数据仓库的数据是集成的;数据仓库的数据是稳定的;数据仓库的数据是随时间变化的。

阅读理解

阅读理解。

     In the United States, children start school when they are five years old. In some states they must stay in

school until they are sixteen. Most students are seventeen or eighteen years old when they leave secondary (中

等的) schools. There are two kinds of schools in the United States: public schools and private (私立的)

schools. Most children go to public schools. Their parents do not have to pay for their education because the

schools receive money from the government. If a child goes to a private school, his parents have to get enough

money for his schooling. Some parents still prefer private schools, though they are much more expensive.

Today about half of the high school students go to universities after they finish the secondary school. A

student at state university does not have to pay very much if his parents live in that state. But many students

work while they are studying at universities. In this way they develop good working habits and live by their

own hands.

( )1. Children can go to school at the age of four in the U.S.                                                         

( )2. Most parents prefer to send their children to private schools in America.                                        

( )3. About fifty percent of high school students can go on to universities

           after they leave the secondary school today.

( )4. Lots of American students go to universities by depending on their parents

            ompletely (完全地).                  

( )5. The passage is mainly about American education.                                                                  

单项选择题