实现数据库操作的DAO技术,其模型采用的是层次结构,其中处于最顶层的对象是【 】

组织液中的O₂进入组织细胞的线粒体共通过磷脂分子[ ]

A．4层

B．6层

C．3层

D．8层

Pentium微处理器的寄存器组是在8086/8088微处理器的基础上扩展起来的。下面是关于Pentium微处理器中寄存器组的叙述，其中正确的是( )。

A．所有的寄存器都是从16位扩展为32位

B．EAX、EBX、ECX、EDX、ESP、EBP、ESI和EDI既可作为32位也可作为16位或8位寄存器使用

C．选项B)中的所有寄存器既可存放数据，也可作为基址或变址寄存器使用

D．段寄存器从4个增加到6个

美国心理学家亚当斯提出的激励理论是（ ）

A．公平理论

B．双因素理论

C．期望理论

D．需要层次理论

对袢环结构模型叙述正确的是（）

A．核小体折叠成一系列袢环结构域

B．螺线管折叠成一系列袢环结构域

C．超螺线管折叠成一系列袢环结构域

D．袢环基部连接在组蛋白支架上

E．袢环基部连接在核纤层支架上

What is a knowledge worker Knowledge workers are people who routinely use a computer in their work to enhance their productivity. She or he is the critical component in a computer system. A computer system is made up of people, using data and procedures to work with software and hardware components. It takes all five working together to produce results. Knowledge workers are white-collar professionals from many walks of life who have the following characteristics.

They understand how to use a personal computer.

They know how to work with computer-based information.

They understand how the computer benefits their work and the business.

They regard the computer as a productivity tool.

Knowledge workers may be employed in a company of any size, large or small, at a wide range of tasks. They may be self-employed, working in their own office or at home. They may be sales representatives or managers who travel with a portable computer. Students are knowledge workers as well. Many of you may be preparing for a career in knowledge work in office automation, public relations, account supervision, social work, management, or a number of other occupations.

Today, there are over 70 million knowledge workers in the United States, who generate nearly 2 trillion pieces of paper each year. These knowledge workers work 10 hours per week more than they did 10 years ago, and create over 15 billion new pieces of paper a year. According to a survey conducted by Industry Week magazine in 1990, 39 percent of U. S. management-level knowledge workers say paperwork is a problem. Further, USA Today reported in 1991 that the average knowledge worker has 36 hours of work stacked up on the desk. Clearly, the computer as a productivity tool must play an ever more important role in knowledge work and knowledge work itself is steadily assuming larger proportions. According to several worldwide studies, urban centers in Canada, the United States, Europe, and other developed areas are increasingly using computer technology and thus evolving knowledge-based cities. These knowledge-based cities are characterized by. (1) a concentration of scientists and engineers, (2) business, university, and governmental research activities, (3) a high degree of interaction between individuals and the various institutions, and (4) a positive image that attracts college graduates to knowledge work. Clearly, the decade of the 1990s and the new millennium that follows are an exciting time for knowledge work.

The five components of a computer systems are ().

A. knowledge worker, computer, date, software, results

B. knowledge worker, data, procedures, software, hardware

C. people, computer, information, work, results

D. not mentioned