问题 单项选择题

一个教师可讲授多门课程,一门课程可由多个教师讲授,则实体教师和课程间的联系是( )。

A) 1:1联系
B) 1:m联系
C) m:1联系
D) m:n联系

答案

参考答案:D

解析: 两个实体间的联系可以归纳为3种类型。
一对一联系:一对一的联系表现为主表中的每一条记录只与相关表中的一条记录相关联。
一对多联系或多对一联系:一对多的联系表现为主表中的每一条记录与相关表中的多条记录相关联。
多对多联系:多对多的联系表现为一个表中的多个记录在相关表中同样有多个记录与其匹配。
一个教师可讲授多门课程,一门课程可由多个教师讲授,所以实体教师和课程间的联系是多对多的联系。

阅读理解

阅读理解。

    Jenny and Henry were born on the same day and they look the same. Their father has a taxi (出租车) and

he is busy all the time. He goes out early in the morning but comes back when his children go to bed. He gets

a lot of money, but he has no time to concern them with their studies.

    The two children study in the same class. Jenny works hard at her lessons, but her brother doesn't like

studying. He only likes playing. He is not good at writing compositions (作文). 

    One day Mrs. Cook tells her class to write a composition "My Mother". After supper Jenny finishes writing

in her exercise book and then goes to help her mother do some housework. But Henry goes to play football.

When night falls (降临), he comes back to watch TV. Then he remembers (记得) the composition. But he

doesn't know how to write it. He thinks hard and at last he finds a way. He copies (抄写) Jenny's composition.

    Two days later, Mr Cook asks Henry, "Can you tell me why yours is the same as Jenny's?"

    "Yes, I can, Madam," answers Henry. "We have the same mother."

1. Jenny's father can't concern them with their studies because            . [ ]

A. he doesn't like them

B. he is very busy

C. he is a taxi driver

D. he only wants more (更多的) money

2. The underlined (划线的) word "concern" in the story means (意思是)            . [ ]

A. 涉及

B. 关系

C. 当然

D. 关心

3. Henry isn't good at writing composition because            . [ ]

A. he doesn't like studying

B. he likes listening to music

C. he isn't clever

D. he's too young to do it

4. What does Jenny do after she finishes the composition? [ ]

A. Go shopping.

B. Watch TV.

C. Do housework.

D. Go to bad.

5. Henry copies Jenny's composition because            . [ ]

A. he plays football after supper

B. he forgets (忘记) to write it before he goes to bed

C. he doesn't know how to write it

D. they have the same mother

多项选择题