问题 单项选择题

在下列关于关系型数据库系统的叙述中,正确的是

A.表的字段之间和记录之间都存在联系

B.表的字段之间和记录之间都不存在联系

C.表的字段之间不存在联系,而记录之间存在联系

D.表中只有字段之间存在联系

答案

参考答案:A

解析:[分析] 在关系数据库系统中,数据库中的数据存储在二维表中,而表由记录构成,每个记录都具有相同的结构,即每个记录的所包含的属性类型相同,而取值不同,并且在数据库的表中,通常会设定某个字段或某些字段为键,通过这些键就可以确定其他字段的值,因此在关系型数据库系统中,表的字段之间和记录之间都存在联系,正确答案应该是A。

阅读理解

阅读理解。

     As kids, my friends and I spent a lot of time out in the woods. "The woods" was our part-time address,

destination, purpose and excuse. If I went to a friend's house and found him not at home, his mother might

say, "Oh, he's out in the woods," with a tone (语气) of airy acceptance. It's similar to the tone people

sometimes use nowadays to tell me that someone I'm looking for is on the golf course or at the gym, or even

"away from his desk." For us ten-year-olds, "being out in the woods" was just an excuse to do whatever we

feel like for a while.

     We sometimes told ourselves that what we were doing in the woods was exploring (探索). Exploring was

a more popular idea back then than it is today. History seemed to be mostly about explorers. Our explorations,

though, seemed to have less system than the historic kind: something usually came up along the way. Say we

stayed in the woods, throwing rocks, shooting frogs, picking blackberries, digging in what we were briefly

persuaded was an Italian burial mound.

     Often we got "lost" and had to climb a tree to find out where we were. If you read a story in which

someone does that successfully, be skeptical: the topmost branches are usually too skinny to hold weight, and

we could never climb high enough to see anything except other trees. There were four or five trees that we

visited regularly-tall beeches, easy to climb and comfortable to sit in.

     It was in a tree, too, that our days of fooling around in the woods came to an end. By then some of us has

reached seventh grade and had begun the rough ride of adolescence (青春期). In March, the month when we

usually took to the woods again after winter, two friends and I set out to go exploring. We climbed a tree, and

all of a sudden it occurred to all three of us at the same time that were really rather big to be up in a tree. Soon

there would be the spring dances on Friday evenings in the high school cafeteria.

1. The author and his friends were often out in the woods to _____. [ ]

A. spend their free time

B. play golf and other sports

C. avoid doing their schoolwork

D. keep away from their parents

2. What can we infer from Paragraph 2? [ ]

A. The activities in the woods were well planned.

B. Human history is not the result of exploration.

C. Exploration should be a systematic activity.

D. The author explored in the woods aimlessly.

3. The underlined word "skeptical" in Paragraph 3 is closest in meaning to _____. [ ]

A. calm

B. doubtful

C. serious

D. optimistic

4. How does the author feel about his childhood? [ ]

A. Happy but short.

B. Lonely but memorable.

C. Boring and meaningless.

D. Long and unforgettable.

单项选择题 案例分析题