下列程序的执行结果是（ ）。　　public class Testdd {

.瞳距仪上“R”数值表示（）瞳距。

Traditional Internet access methods like dial-up were so slow that host computers were connected to the dial-up. (6) at the customer premise over slow (7) ports. PPP was designed to run directly over these serial links. But with the advent of broadband Internet (8) technologies such as ADSL and cable modems there has been a considerable increase in the bandwidth delivered to the end users. This means that the host computers at the customer premise connect to the (9) or cable "modem" over a much faster medium such as Ethernet. It also means that multiple (10) can connect to the Internet through the same connection.

（6）是（）

A.buffer

B.modem

C.computer

D.server

一个由高速缓冲存储器Cache与主存储器组成的二级存储系统。已知主存容量为1MB，按字节编址，缓存容量为32KB，采用组相连方式进行地址映射与变换，主存与缓存的每一块为64B，缓存共分8组。

假定Cache的存取周期为20μs，命中率为0.95，希望采用Cache后的加速比大于10。那么主存储器的存取速度应大于多少(访存时CPU同时访问Cache和主存，如Cache命中则中断主存访问)

晕厥连续出现几次后永远不宜献血（）

A.2次

B.3次

C.4次

D.5次