A、AG

B、IP PBX

C、IAD

D、SIP GW

A分组封装帧

B帧封装分组

C分组封装报文

D报文封装分组

A.释放应答报文

B.连接建立报文

C.紧急数据报文

D.捎带应答报文

、作者，一个作者可以写多本书，而一本书可以同时有多个作者，那么书与作者之间的关联是()。

A、many-to-one?

B、one-to-many?

C、one-to-one??

D、many-to-many

A.变更取消仅邮件通知业务人员

B.提前发起变更申请确认变更时间

C.通知业务相关人员做好业务启停准备

D.提前准备好变更失败的回退操作

A.3次握手

B.端口机制

C.自动重发

D.滑动窗口协议

A、extrude

B、lathe

C、bevel

D、bevel profile

A、快捷检查

B、调度检查

C、基线管理

D、离线检查

A、SELECT JOB_ID , DEPARTMENT_ID , AVG(SALARY)

FROM EMPLOYEES GROUP BY JOB_ID

HAVING AVG(SALARY) >3000;

B、SELECT JOB_ID , DEPARTMENT_ID , AVG(SALARY)

FROM EMPLOYEES GROUP BY JOB_ID ,DEPARTMENT_ID

HAVING AVG(SALARY) >3000;

C、SELECT JOB_ID , DEPARTMENT_ID , AVG(SALARY)

FROM EMPLOYEES GROUP BY AVG(SALARY)

HAVING AVG(SALARY) >3000;

D、SELECT JOB_ID , DEPARTMENT_ID , AVG(SALARY)

FROM EMPLOYEES GROUP BY JOB_ID , DEPARTMENT_ID

HAVING SALARY >3000;

A.传输层

B.网络层

C.LLC子层

D.MAC子层