问题 单项选择题

数据库系统的核心是( )。

A.数据库

B.数据库管理系统

C.模拟模型

D.软件工程

答案

参考答案:B

解析:数据库管理系统(Database Management System,简称DBMS)是数据库的机构,它是一种系统软件,负责数据库中的数据组织、数据操纵、数据维护、控制及保护和数据服务等,数据库管理系统是数据库系统的核心。

单项选择题

For many people today, reading is no longer relaxation. To keep up their work they must read letters, reports, trade publications, interoffice communications, not to mention newspapers and magazines: a never-ending flood of words.
In (36) a job or advancing in one, the ability to read and comprehend (37) can mean the difference between success and failure. Yet the unfortunate fact is that most of us are (38) readers.
Most of us develop poor reading (39) at an early age, and never get over them. The main deficiency (40) in the actual stuff of language itself—words. Taken individually, words have (41) meaning until they are strung together into phrases, sentences and para-graphs. (42) , however, the untrained reader does not read groups of words. He laboriously reads one word at a time, often regressing to (43) words or passages.
Regression, the tendency to look back over (44) you have just read, is a common bad habit in reading. Another habit which (45) down the speed of reading is vocalization—sounding each word either orally or mentally as (46) reads. To overcome these bad habits, some reading clinics use a device called an (47) , which moves a bar (or curtain) down the page at a predetermined speed. The bar is set at a slightly faster rate (48) the reader finds comfortable, in order to "stretch" him.
The accelerator forces the reader to read fast, (49) word-by-word reading, regression and sub vocalization, practically impossible. At first (50) is sacrificed for speed. But when you learn to read ideas and concepts, you will not only read faster, (51) your comprehension will improve.
Many people have found (52) reading skill drastically improved after some training. (53) Charlce Au, a business manager, for instance, his reading rate was a reasonably good 172 words a minute (54) the training, now it is an excellent 1,378 words a minute. He is delighted that how he can (55) a lot more reading material in a short period of time.

[A] Look at[B] Take[C] Make[D] Consider

不定项选择