问题 填空题

数据的独立性分为逻辑独立性与物理独立性。当数据的存储结构改变时,其逻辑结构可以不变,因此,基于逻辑结构的应用程序不必修改,这称为______。

答案

参考答案:物理独立性

解析: 数据的独立性是指数据和应用程序相互独立,分为物理独立性和逻辑独立性。其中物理独立性是指数据的物理结构(包括存储结构、存取方式)改变时,不需要修改应用程序。而逻辑独立性是指当逻辑结构改变时,不需要修改应用程序。

阅读理解

阅读理解。

     A mother and her son got into a bus in a small city and sat down.  The bus conductor came to them

 for their money.  The mother said, "I want one ticket to Oxford,"and gave him a shilling (先令,1先令等于

 12便士).

     The conductor looked at the small boy for a few seconds and then said to him, "How old are you, little

 friend?"

     The mother began speaking, but the conductor stopped her, and the boy said, "I'm four years old at

 home, and two and a half in buses and trains.  "

     The mother took six pence (便士) out of her bag and gave the money to the conductor.  The

 conductor gave her one and a half tickets.  

1.  One day the mother took a bus _____.

    A.  to a small city  

    B.  to get some money    

    C.  with her son    

    D.  to get a ticket

2.  The mother gave the conductor _____ pence in all(总共)that day.

    A.  12  

    B.  16  

    C.  10  

    D.  18

3.  The mother was _____.

    A.  not honest (诚实的)    

    B.  honest    

    C.  very clever    

    D.  not clever

4.  _____ told him to say, "I'm four years old at home,and two and a half in buses and trains.  "

    A.  The conductor    

    B.  The boy's father    

    C.  The boy's mother    

    D.  The driver

5.  The boy was really _____ years old.  

    A.  four    

    B.  two    

    C.  two and a half    

    D.  six and a half

单项选择题 A1/A2型题