EXCEL图表是动态的，当在图表中修改了数据系列的值，与图表相关的工作表中的数据（）

A、出现错误值

B、不变

C、自动修改

D、用特殊颜色显示

Which two statements are true regarding an Ethernet collision domain?（）

If a switch is used, the collision domain is limited to each device and the switch.

If a hub is used, the collision domain is limited to each device and the hub.

If a hub is used, the collision domain includes all devices connected to the hub.

If a switch is used, the collision domain includes all devices connected to the switch.

下列运算符中，不能被重载的是（　　）。

A、&&

B、!=

C、.

D、++

假设磁盘上每个磁道划分成9个物理块，每块存放1个逻辑记录。逻辑记录R0，R1，…，R8存放在同一个磁道上，记录的安排顺序如表1-7所示。假定磁盘旋转一圈的时间为27ms，磁头当前处在R0的开始处。若系统顺序处理这些记录，使用单缓冲区，每个记录处理时间为3ms，则处理这9个记录的最长时间为（1）；若对信息存储进行优化分布后，处理9个记录的最少时间为（2）。空白（2）处应选择（）

A、30ms

B、36ms

C、54ms

D、60ms

In your database, the LDAP_DIRECTORY_SYSAUTH initialization parameter has been set to YES and the users who need to access the database as DBAs have been granted SYSDBA enterprise role in Oracle Internet Directory (OID). SSL and the password file have been configured. A user SCOTT with the SYSDBA privilege tries to connect to the database instance from a remote machine using the command: Which authentication method would be used first?（）

A、 authentication by password file

B、 authentication by using certificates over SSL

C、 authentication by using the Oracle Internet Directory

D、 authentication by using the local OS of the database server

10. abstract public class Employee {  11. protected abstract double getSalesAmount（）；  12. public double getCommision（） {  13. return getSalesAmount（） * 0.15；  14. }  15. }  16. class Sales extends Employee {  17. // insert method here  18. }  Which two methods， inserted independently at line 17， correctly complete the Sales class？（）

 double getSalesAmount（） { return 1230.45； }

 public double getSalesAmount（） { return 1230.45； }

 private double getSalesAmount（） { return 1230.45； }

 protected double getSalesAmount（） { return 1230.45； }