化学降解法中，由于化学切割反应并非完全绝对的单一碱基特异性，因此除G,C残基外，A,T残基的位置需结合其他泳道的条带加以推断。

A残基的位置推断需结合的泳道是

A:A组 B:G+A组 C:G组和G+A组 D:C+T组 E:C组和C+T组

化学降解法中，由于化学切割反应并非完全绝对的单一碱基特异性，因此除G,C残基外，A,T残基的位置需结合其他泳道的条带加以推断。

T残基的位置推断需结合的泳道是

A:T组 B:G+A组 C:G组和G+A组 D:C+T组 E:C组和C+T组

Tracking Down HIV

    In the summer of 1980, a patient had a strange purplish spot removed from below his ear. It was Kaposi’s sarcoma, a rare form of skin cancer. This patient also had lymph node swelling and exhaustion. In November 1980, a Los Angelesimmunologist examined a young man who had diseases linked to immune system malfunctions. The doctor had a T-cell count taken of the patient’s blood. T-cells are a type of white blood cell that plays a key role¹ in immune responses. The patient had no helper T-cells.

    By the end of 1980, 55 Americans were diagnosed with infections related to immune system breakdown; four had died. A year later the death toll was 74. Intravenous drug users had T-cell abnormalities. People who had received blood transfusions showed symptoms of immune system breakdown. By July 1982, 471 cases of the disease, now called Acquired Immune Deficiency Syndrome (AIDS), had been reported; 184 people had died.

    In April 1984, American virologist Dr. Robert Gallo isolated the pathogen, or disease producer, responsible for² AIDS. He called it HTLV-III. InParis, Dr. Luc Montagnier identified a virus he called LAV. An international panel of scientists determined that both men had found the same virus. It became known as Human Immunodeficiency virus (HIV). Blood banks began screening for HTV in 1985, but by then about 29,000 people had been infected through blood transfusions. Some 12,000 hemophiliacs had contracted HIV through blood-clotting products. By 1995, 477,900 Americans had AIDS; 295,500 had died.

    In 1996, researchers announced drugs that reduced HIV in infected people. Today scientists are testing vaccines and believe that if HIV can be suppressed, then perhaps it can be eradicated³, but it is still a race against time.

词汇：

spot [spɒt] n. 地点，斑点，斑块，青春痘

lymph [lɪmf] n. 淋巴结

sarcoma [sɑ:"kəʊmə] n. 肿瘤，肉瘤，恶性毒瘤

exhaustion [ɪgˈzɔ:stʃən] n. 衰竭，耗尽，精疲力竭

immunologist [ɪgˈzɔ:stʃən] n. 免疫学家

malfunction [ˌmæl"fʌŋkʃn] n. 故障，失灵，疾病

count [kaʊnt] n. 计数，计算

infection [ɪn"fekʃn] n. 传染病，感染

breakdown ["breɪkdaʊn] n. 故障，衰弱，崩溃

toll [təʊl] n. 代价，死亡人数

intravenous drug n. 静脉注射药物

abnormalities [ˌæbnɔ:"mælɪtɪz] n. (abnormality的复数形式)畸形，异常情况

blood transfusion n. 输血

symptom ["sɪmptəm] n. 症状

virologist [vaɪ"rɒlədʒɪst]c n. 病毒学家

virus ["vaɪrəs] n. 病毒

panel ["pænl] n. 座谈小组，仪表板

hemophiliac [ˌhi:mə"fɪlɪæk] n. 血友病患者

vaccine ["væksi:n] n. 疫苗

注释：

1．play a key role...扮演一个关键角色，有至关重要的作用

2．be responsible for...对……负责，是……的原因

A T-cell is a ____.

A:patient’s blood B:deadly strain of tuberculosis C:white blood cell important in providing immunity to disease D:red blood cell

Netstat工具可以用来显示协议的有关统计信息和当前TCP/IP的连接状况使用该命令的哪个参数可以只显示指定协议的相关信息（）

A:Netstat-e B:Netstat-n C:Netstat-r D:Netstat-p

命令netstat-a停了很长时间没有响应，这可能是哪里的问题？（）

A:NFS. B:DNS. C:NIS. D:routing.

netstat的作用是（）。

A:显示进程处理状态 B:运行图形处理软件 C:让系统停机 D:显示当前网络状态

发现子公司A的某台PC无法访问Web服务器，作如下检查。
①查看“网上邻居”，发现该P，C可以访问子公司A内其他主机。
②采用 (1) 命令来检查与路由器接口1的连通性，结果正常。
③该PC可以通过域名访问FTP服务器。
④用SHOW ACCESS-LIST命令检查路由器的 (2) ，发现有问题，那么造成该PC无法访问Web服务器的原因可能是 (3) 。
A．oinz B．nslookup C．netstat D．interface

A:oinz B:nslookup C:netstat D:interface

能显示如图3-1所示的IPv6统计信息的Windows命令是 (12) 。

A:netstat-an B:netstat-p IPv6 C:netstat-e D.netstat-s

若进行网络配置不后不能进入Internet服务，ping 127.0.0.1是通的，ping网关不通，给出 (55) 的结论是不正确的。
需要确定TCP/IP是否已经初始化，或者在NT上是否配置了重复的IP地址，要使用程序 (56) 关于ping的使用，其正确的格式是 (57) 。
用ping检测网络， (58) 命令是以IP地址格式来显示目标主机的网络地址的。netstat命令可以使用户了解主机如何与因特网相连接，netstat--s的作用是 (59) 。

A:ARP B:ICMP C:Netstat D:ping