FTTx+LAN是实现宽带接入的常用方式，基本结构如图12-10所示。本方案采用DHCP来分配网络地址。DH-CP是 (46) 协议的一个扩展，便于客户自动从服务器获取IP地址和相关设置，其中实现IP地址动态分配的过程如下：((1)～(4)未按顺序排序)
(1)客户设置服务器ID和IP地址，并发送给服务器一个DHCPREQUEST报文；
(2)客户端向服务器广播DHCPDISCOVER报文，此报文源地址为 (47) ，目标地址为 (48) ；
(3)服务器返回DHCPACK报文；
(4)服务器返回DHCPOFFER报文。
客户收到的数据包中应包含客户的 (49) 地址，后面跟着服务器能提供的IP地址、子网掩码、租约期限以及DHCP服务器的 (50) 地址。客户进行ARP检测，如果觉得有问题，发送DHCPDECLINE报文；如果觉得没有问题，就接受这个配数参数。
47（）
参考答案：0.0.0.0
| 完形填空. | |||
| It was Mother's Day. I was so busy with my work that I couldn't 1 back home. When I passed by a 2 shop, a(n) 3 came to my mind, "I'll send Mum some roses." While I was 4 my flowers, a young man went inside. "How many roses can I get 5 only five dollars, Madam?" he asked. The assistant was trying to tell him roses were as 6 as forty dollars a dozen - maybe he would be happy with carnations(康乃馨). "No, I 7 have red roses." he said, "my mum was 8 ill last year and I didn't spend much time with her. Now I want to get something special, roses, as rose is her ." After hearing it, I said I would pay 10 of the money for the young man. 11 by both of us, the assistant said, "Well, lovely young man, thirty dollars a dozen, only for you." Taking the roses, the young man almost jumped into the 12 and ran out of the shop. It was 13 worth twenty-five dollars I paid to see the exciting 15 . Then I paid for my dozen of roses and told the assistant to 14 them to my mother. As I walked out, I felt 16 . Suddenly I saw the young man crossing the street and going into a park. But soon I 17 it was not a park 18 a cemetery(公墓). Crying, the young man carefully 19 the roses, "Mum, why didn't I tell you how much I loved you? God, please help me find my mum and tell her I love her." Seeing this, I turned and quickly walked to the 20 . I would take the flowers home myself. | |||
| ( )1.A. go ( )2.A. vegetable ( )3.A. fact ( )4.A. picking ( )5.A. with ( )6.A. much ( )7.A. might ( )8.A. a bit ( )9.A. flower ( )10.A. all ( )11.A. Surprised ( )12.A. roses ( )13.A. very ( )14.A. moment ( )15.A. give ( )16.A. relaxed ( )17.A. understood ( )18.A. and ( )19.A. laid ( )20.A. man | B. come B. clothing B. word B. watering B. for B. cheap B. have to B. hardly B. favorite B. some B. Pleased B. assistant B. well B. time B. offer B. amazed B. realized B. or B. lay B. street | C. return C. rose C. idea C. selling C. at C. expensive C. should C. badly C. dream C. the rest C. Excited C. air C. not C. scenery C. present C. shameful C. learned C. nor C. buried C. shop | D. turn D. flower D. picture D. showing D. on D. high D. can D. nearly D. gift D. much D. Moved D. street D. only D. incident D. send D. nice D. told D. but D. grew D. cemetery |