Cloud computing is a phrase used to describe a variety of computing concepts that involve a large number of computers_（ ）__through a real-time communication network such as the Internet.In science,cloud computing is a_（ ）__for distributed computing over a network,and means the_（ ）_to run a program or application on many connected computers at the same time.The architecture of a cloud is developed at three layers:infrastructure,platform,and application.The infrastructure layer is built with virtualized compute，storage，and network resources.The platform layer is for general-purpose and repeated usage of the collection of software resources.The application layer is formed with a collection of all needed software modules for SaaS applications.The infrastructure layer serves as the_（ ）__for building the platform layer of the cloud.In turn,the platform layer is foundation for implementing the_（请作答此空）__layer for SaaS application.
A.resource
B.service
C.application
D.software

以编译方式翻译C/C++源程序的过程中，判断表达式的除数是否为零是（）的任务。
A.词法分析
B.语义分析
C.语法分析
D.目标代码生成

在以阶段划分的编译器中，符号表管理和（）贯穿于编译器工作始终。
A.代码生成
B.语法分析
C.语义分析
D.出错处理

In the fields of physical security and information security, access control is the selective restriction of access to a place or other resource. The act of accessing may mean consuming, entering, or using. Permission to access a resource is called authorization （授权）．
An access control mechanism （71） between a user （or a process executing on behalf of a user） and system resources, such as applications, operating systems, firewalls, routers, files, and databases. The system must first authenticate（验证）a user seeking access. Typically the authentication function determines whether the user is （72） to access the system at all. Then the access control function determines if the specific requested access by this user is permitted. A security administrator maintains an authorization database that specifies what type of access to which resources is allowed for this user. The access control function consults this database to determine whether to（73）access. An auditing function monitors and keeps a record of user accesses to system resources.
In practice, a number of（74）may cooperatively share the access control function. All operating systems have at least a rudimentary（基本的）, and in many cases a quite robust, access control component. Add-on security packages can add to the（75）access control capabilities of the OS. Particular applications or utilities, such as a database management system, also incorporate access control functions. External devices, such as firewalls, can also provide access control services.
A.remote
B.native
C.controlled
D.automated

从未排序的序列中依次取出一个元素与已排序序列中的元素进行比较，然后将其放在已排序序列的合适位置上，该排序方法为（）。
A.插入排序
B.选择排序
C.快速排序
D.冒泡排序

如果在查找路由表时发现有多个选项匹配，那么应该根据__1____原则进行选择。假设路由表有4个表项如下所示，那么与地址139.17.179.92匹配的表项是__2____。
2、_____
A.139.17.145.32
B.139.17.145.64
C.139.17.147.64
D.139.17.177.64