The computer virus is an outcome of the computer overgrowth in the 1980s. The cause of the term computer virus is the likeness between the biological virus and the evil program infected with computers. The origin of this term came from an American science fiction The Adolescence of P-1written by Thomas J. Ryan, published in 1977. Human viruses invade a living cell and turn it into a factory for manufacturing viruses. However, computer viruses are small programs. They replicate by attaching a copy of themselves to another program.

　Once attached to the host Program, the viruses then look for other programs to infect.In this way, the virus can spread quickly throughout a hard disk or an entire organization when it infects a LAN or a multi-user system. At some point, determined by how the virus was programmed the virus attacks. The timing of the attack can be linked to a number of situations, including a certain time or date, the presence of a particular file, the security privilege level of the user, and the number of times a file is used. Likewise, the mode of attack varies. So-called benign viruses might simply display a message, like the one that infected IBM's main computer system last Christmas with a season's greeting. Malignant viruses are designed to damage the system. The attack is to wipe out data, to delete flies, or to format the hard disk.

　What Kind of Viruses Are There? There are two main types of viruses: shell, intrusive. Shell viruses wrap themselves around a host program and don't modify the original program. Shell programs are easy to write, which is why about half of viruses are of this type. Intrusive viruses invade an existing program and actually insert a portion of themselves into the host program. Intrusive viruses are hard to write and very difficult to remove without damaging the host file.

　參考譯文：

　計(jì)算機(jī)病毒是八十年代計(jì)算機(jī)飛速發(fā)展帶來(lái)的結(jié)果，計(jì)算機(jī)病毒這一名詞起因于在計(jì)算機(jī)上傳染的有害程序與生物學(xué)中病毒的相似性，該名詞起源于1977年出版的、由ThomasJ.Ryan寫(xiě)的一本美國(guó)科幻小說(shuō)《p-1的青春》。人體病毒入侵活的細(xì)胞后，就把它轉(zhuǎn)變成制造病毒的工廠。而計(jì)算機(jī)病毒是一些小程序，它們把自己的一個(gè)副本附加到另一個(gè)程序上面進(jìn)行復(fù)制。

　病毒程序一旦附加到一個(gè)主程序上，就開(kāi)始尋找其他可以進(jìn)行“感染”的程序。這樣，病毒就很快地布滿(mǎn)整個(gè)硬盤(pán)，如果病毒感染了一個(gè)局域網(wǎng)或者一個(gè)多用戶(hù)系統(tǒng)，那么就在整個(gè)組織內(nèi)進(jìn)行擴(kuò)散。只有在某個(gè)點(diǎn)上病毒程序才會(huì)發(fā)作(這是由病毒程序的設(shè)計(jì)所決定的)。攻擊的時(shí)間與多種情況有關(guān)，包括：某個(gè)時(shí)間或日期、特定用戶(hù)識(shí)別符的出現(xiàn)、用戶(hù)的安全保密等級(jí)和一個(gè)文件使用的次數(shù)。同樣，攻擊的方式也是各種各樣的。所謂的“良性”病毒可能只是簡(jiǎn)單地顯示一個(gè)消息，如在去年圣誕節(jié)時(shí)，受感染的IBM公司的主要計(jì)算機(jī)系統(tǒng)顯示節(jié)日問(wèn)候。惡性病毒被設(shè)計(jì)出來(lái)破壞系統(tǒng)。常見(jiàn)的攻擊方式是消除數(shù)據(jù)、刪除文件或者格式化硬盤(pán)。

　病毒的種類(lèi)有哪些？主要有兩種病毒：shell病毒和instrusive病毒。Shell病毒把自己盤(pán)繞在主程序周?chē)�，它并不修改原程序。這種病毒容易復(fù)制因此它的數(shù)量占了所有病毒的一半。Instrusive病毒入侵現(xiàn)有程序并且把自己的一部分插入主程序。這種病毒不易復(fù)制，但是很難在不損傷主程序的情況下被刪除。

　重點(diǎn)單詞：

　1、virus 病毒

　2、outcome 結(jié)果

　例句: I think there can be but one outcome to this affair.

　我認(rèn)為這件事只能有一種結(jié)局。

　3、program [電腦]程序

　4、replicate 復(fù)制，折疊，復(fù)制品

　5、host [電腦]主機(jī)

　6、at some point 某時(shí), 某種情況下

　7、so-called 所謂的

　8、malignant 邪惡的，極有害的

　9、data 數(shù)據(jù)

　10、wipe out 消滅；徹底摧毀

　例句: They have wipe out the enemy's major military target.

　他們已經(jīng)徹底摧毀了敵人的主要軍事目標(biāo)。

　句型分析:

　1、The cause(of the term computer virus)is the likeness(between the biological virus and the evil program [infected with computers].)

　2、The timing(of the attack)can be linked to a number(of situations), including [1]a certain time or date, [2]the presence of a particular file, [3]the security privilege level of the user, [4]and the number of times a file is used.

　[1]、[2]、[3]、[4]是在including下的并列短句。