给出定义：
1.Higher level language
A high-level programming language is a programming language with strong abstraction
from the details of the computer. In comparison to low-level programming languages, it may use natural language elements, be easier to use, or be from the specification of the program, making the process of developing a program simpler and more understandable with respect to a low-level language.
2.Stateful inspection
is a firewall that keeps track of the state of network connections (such as TCP streams, UDP communication) traveling across it. The firewall is programmed to distinguish legitimate packets for different types of connections. Only packets matching a known active connection will be allowed by the firewall; others will be rejected.
3. Personal productivity software
4. Metropolitan area network(MAN)
A metropolitan area network(MAN) is a computer network that usually spans a city or a
large campus. A MAN usually interconnects a number of local area networks (LANs) using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks (or WAN) and the Internet.
5. Network topology
Network topology is the layout pattern of interconnections of the various elements (links, nodes, etc.) of a computer or biological network. In a word network topology is the topological structure of a network. Network topologies may be physical or logical. Physical topology refers to the physical design of a network including the devices, location and cable installation.
Logical topology refers to how data is actually transferred in a network as opposed to its physical design. In general physical topology relates to a core network whereas logical topology relates to basic network
6. DBMS
database management system (DBMS) is a software package with computer programs that control the creation, maintenance, and use of a database. It allows organizations to conveniently develop databases for various applications by database administrators (DBAs) and other specialists
简要回答问题：
1.Give the definition and examples about computer virus. （这题书上答案不全，
需要网上搜点答案，组织成答案）
DE: A computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly, but erroneously, used to refer to other types of malware, including but not limited to adware and spyware programs that do not have a reproductive ability.
EX: For example, the CIH virus, or Chernobyl Virus, computer worm.
2.Describe the hierarchy of data organization.
Data organization involves fields, records, files and so on
A data field holds a single fact. Consider a date field, e.g. "September 19, 2004". This can be treated as a single date field (e.g. birthdate), or 3 fields, namely, month, day of month and year.
