某磁盘盘组共有10个盘面，每个盘面上有100个磁道，每个磁道有32个扇区，假定物理块的大小为2个扇区，分配以物理块为单位。若使用位示图（Bitmap）管理磁盘空间，则位图需要占用（1）字节空间。若采用空白文件管理磁盘空间，且空白文件目录的每个表项占用5个字节，则当空白文件数目大于（2）时，空白文件目录占用的字节数大于位图占用的字节数。空白（2）处应选择（）

A、400

B、360

C、320

D、160

ARP协议的功能是（）。

A、由目标的IP地址求目标的MAC地址

B、由目标的MAC地址求目标的IP地址

C、由源的IP地址求源的MAC地址

D、由源的MAC地址求源的IP地址

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.

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； }

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

In your database, the flash recovery area (FRA) is configured as the default for RMAN backups. You executed the following commands to configure the settings in RMAN: Which statement is true about the outcome?（）

A、 Only one channel is allocated and the backup is created in the flash recovery area

B、 Only one channel is allocated and the backup is created in the destination specified for channel

C、 Two channels are allocated and backup sets are created in the destinations specified for channels 1 and 2

D、 Three channels are allocated and backup sets are created in the destinations specified for channels 1, 2, and FRA