简要说明测定归心元素常用的两种方法及他们各适用于什么情况。

阅读理解。

    Mr. Ma, a famous mental doctor (心理医生) from Beijing once said at an important meeting, "Now

many young students can have problems with their minds. Some students become worried because they

have to study very hard. Others have trouble getting on well with people around them like their parents

and classmates. Parents and teachers should care more about this problem."

    Then Mr. Ma gave some examples. A middle school student from Xi'an was doing badly in his lessons.

He thought his teachers and friends often laughed at him, and he became so nervous and worried that one

night he left his home without telling his parents. Another student, a 14-year-old schoolgirl from Shanghai,

was very afraid of exams. While she was reading the exam paper, she couldn't think of anything to write.

    A recent report from a newspaper says about 18% of the young students in Shanghai have mental

problems. They often feel worried and very unhappy. Unluckily many of them won't go and ask for help.

Some think they will look stupid if they go to see a doctor. Others won't talk about their secrets.

    At the end of the meeting, Mr. Ma gave some good ideas to young people: 

    ◆ Talk to your parents or teacher often. 

    ◆ Join in group activities. 

    ◆ Try to get on well with the people around you. 

    ◆ Go to see a doctor if you often feel unhappy.

1. The students who often become worried or have trouble getting on with others may have ______.

A. no parents

B. no secrets

C. poor memories

D. mental problems

2. The schoolgirl's problem happened whenever she ______.

A. studied very hard

B. had exams

C. talked with her parents

D. went to see the doctor

3. Some of those with mental problems won't ask for help because ______.

A. they don't want o tell their secrets to others

B. their parents are too busy to look after them

C. doctors can't help them with the problems

D. they can do with the problems themselves

4. The underlined word "stupid" in this passage means ______.

A. pretty

B. happy

C. not clever

D. not friendly

5. According to the last part, which of the followings is a good idea?

A. It's important for children to live with their parents.

B. It's helpful for people to see doctors every day.

C. It's useful for students to keep quiet in class.

D. It's necessary for young people to have group activities.

如果用手一碰含羞草，含羞草的叶子会合拢，这说明生物具有的特征是（　　）

A．生长

B．繁殖

C．应激性

D．新陈代谢

设备定修是在设备点检、预防检修的条件下进行。

在下列叙述中，错误的一条是______。

A．对关系的描述称为关系模式，一个关系模式对应一个关系的结构

B．不同元组对同一个属性的取值范围称为域

C．二维表中的行称为属性

D．所谓关键字，即属性或属性组合，其值能够惟一标识一个元组

丰镐遗址