问题 单项选择题

通过读优盘、光盘(CD-ROM)及各种移动存储介质感染______。

A.引导区型病毒

B.文件型病毒

C.混合型病毒

D.宏病毒

答案

参考答案:A

解析: 计算机病毒分为: ①引导区型病毒。通过读优盘、光盘(CD-ROM)及各种移动存储介质感染引导区型病毒。这类病毒常常将其病毒程序替代主引导中的系统程序。引导区病毒总是先于系统文件装入内存储器,获得控制权并进行传染和破坏。选项A正确。 ②文件型病毒。文件型病毒主要感染扩展名为.COM、.EXE、.DRV、.BIN、.OVL、.SYS等可执行文件。 ③混合型病毒。既可以传染磁盘的引导区,也传染可执行文件,兼有上述两类病毒的特点。 ④宏病毒。宏病毒只感染Microsoft Word文档文件(DOC)和模板文件(DOT),与操作系统没有特别的关联。能通过软盘文档的复制、E-mail下载Word文档附件等途径蔓延。 ⑤Internet病毒(网络病毒)。Internet病毒大多是通过E-mail传播。

单项选择题

When a disease of epidemic proportions threatens the public, scientists immediately get to work, trying to locate the source of affliction and find ways to combat. Vaccination is one of the effective ways to protect the (1) population of a region or country which may be (2) grave risk. The process of vaccination allows the patient’s body to (3) immunity to the virus or disease so that, if it is encountered, one can fight it (4) naturally. To accomplish this, a small weak or dead (5) of the disease is actually injected into the patient in a controlled environment, (6) his body’s immune system can learn to fight the invader (7) . Information (8) how to penetrate the disease’s defenses is (9) to all elements of the patient’s immune system in a process that occurs naturally, in which genetic information is passed from cell to cell. This makes sure that (10) the patient later come into contact with the real problem, his body is well equipped and trained to (11) with it, having already done so before.

There are, however, dangers (12) in the process. (13) , even the weakened version of the disease contained in the vaccine proves (14) much for the body to handle, resulting in the immune system (15) , and, therefore, the patient’s death. Such is the case of the smallpox vaccine, (16) to eradicate the smallpox epidemic that nearly (17) the whole Native American population and killed massive numbers of settlers. (18) 1 in 10,000 people who receive the vaccine (19) the smallpox disease from the vaccine itself and dies from it. Consequently, the process, which is truly a (20) , may indeed hide some hidden curses.

2()

A.in

B.at

C.under

D.beyond

问答题 简答题