“学生—选课—课程”数据库中的三个关系 S(S#,SNAME,SEX,AGE,DE

题型:单项选择题

问题:

“学生—选课—课程”数据库中的三个关系
S(S#,SNAME,SEX,AGE,DEPARTMENT),主码是S=
C(C#,CNAME,TEACHER),主码是C#
SC(S#,C#,GRADE),主码是(S#,C#)

下列关于保持数据库完整性的叙述中,( )是不正确的。

A.向关系SC插入元组时,S#和C#都不能是空值(NLTL)

B.可以任意删除关系SC 中的元组

C.向任何一个关系插入元组时,必须保证关系主码值的唯一性

D.可以任意删除关系C中的元组

考点:计算机等级考试数据库技术三级数据库技术笔试
题型:单项选择题

比较大小:|(-7)+(-6)|______|-7|+|-6|.

题型:单项选择题

患者男,65岁,20年前健康体检时出现"心电图异常",近2个月来,发作2次,走路时眼前发黑。查体:心率40次/分,节律规整,可闻及大炮音。BP130/80mmHg。

病态窦房结综合征的主要心电图表现包括()

A.非药物引起的持续而显著的窦性心动过缓

B.窦性停搏

C.窦房传导阻滞与房室传导阻滞

D.心动过缓-心动过速综合征

E.右束支传导阻滞

F.心脏固有心率超过80次/分

G.房性期前收缩

H.室性期前收缩

I.阵发性房颤

题型:单项选择题

阅读理解。

     Angus MacLeod was fifty and he had spent his entire life as a shepherd in the remote mountainous region

of northwest Scotland. He had never owned a radio or television nor had he travelled further than forty

kilometres from his birthplace. His knowledge of the world was gained only from his brief trips to the village

to sell his sheep and buy food. However, he had lately come to rely on the growing number of hill-walkers in

the region as sources of international news.

     In the spring of 1992, a Spanish student came across Angus high in the mountains. Eager to practise his

English he engaged Angus in conversation. The student told Angus of the forthcoming Olympic Games in

Barcelona. Excited by the student's colourful description of Spain and the Games, Angus decided to attend

the event in person and two months later arrived in Barcelona.

     The ticketless Angus stood outside the stadium with his canny brain working overtime, watching a growing

number of individuals entering the stadium through a small entrance at the side. He noticed that they all seemed

to be carrying objects. Perhaps they were workmen, he thought. He moved closer and watched.

     Within minutes a thin young man came along carrying an extremely long pole. He approached the official

at the door and said "Pole Vault". The official moved to the side and the man entered. Next came a heavy-set

man with a spear. Angus wondered how a man could carry such a dangerous weapon in a modern city. The

man shouted "Javelin" and was presently admitted. Angus was puzzled. Perhaps they were all connected with

security. His puzzlement grew when a huge man appeared with a steel ball in his hand. He shouted "Shot Putt"

and walked past the official.

     It suddenly dawned on Angus that these people were competitors. He opened his programme and sure

enough under the heading "events" he saw the three words the men had said. Angus laughed to himself as a

plan began to take shape in his mind. First he needed to buy one or two things.

     An hour later he reappeared dressed in a tracksuit with "Scotland" written across the chest. Over his shoulder

he carried a roll of barbed wire (铁丝网). Smiling to himself he walked up to the official and as casually as he

could, shouted, "Fencing!"

1. Which was Angus' new way of getting information about the outside world? [ ]

A. Travelling from his birthplace.

B. Listening to radio and watching TV.

C. Going to the nearby village to sell sheep.

D. Talking to hill-walkers in the region.

2. What are "Javelin", "Pole Vault","Shot Putt" and "Fencing" in the passage? [ ]

A. Olympic events.

B. Names of competitors.

C. Security weapons.

D. Names of countries.

3. From the passage we can learn that _____. [ ]

A. more and more people went to Scotland to practise their English

B. the Spanish student's description of his country excited Angus

C. Angus had been planning a trip to Barcelona to see the Olympic Games

D. Angus became a member of the Scottish Olympic team

4. From the passage we know that Angus seemed to be _____. [ ]

A. poorly-informed

B. intelligent

C. strong-minded

D. athletic

5. What do you expect the official would do in the end? [ ]

A. Help him carry the wire.

B. Refuse to let him in.

C. Give him a close inspection.

D. Lead him to the competition.

题型:单项选择题

在因特网中,一般采用的网络管理模型是( )。

A) 浏览器/服务器
B) 客户机/服务器
C) 管理者/代理
D) 服务器/防火墙

题型:单项选择题

轨道电路区段内的轨距杆必须安装()。

A、没有要求

B、带绝缘的轨距杆

C、普通轨距杆

D、不能安装轨距杆

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