第17题: [单项选择]{{B}}Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. She bought him a case for his coin collection. B. She has not bought him a gift yet. C. She bought him a book. D. She bought him a watch. 参考答案:D 答案解析:[听力原文]
M: Do you have your Christmas shopping done yet
W: Almost. I got a watch for my dad. He wo
第20题: [单项选择]下面有关计算机病毒的叙述中,正确的是【 】。 A. 防病毒软件要经常更新其病毒搜索引擎程序和病毒代码库 B. PC机只要安装了某种优秀的病毒防火墙软件,就不可能被病毒所感染 C. 病毒只会感染一些可执行程序,不会感染、破坏数据文件 D. 只要用户不收发电子邮件,PC机就不会被病毒通过网络感染 参考答案:A 答案解析:本题考查Windows98系统的安全与病毒防治。因为病毒经常更新,所以防病毒软件也要经常更新,因此A是正确的。PC机即使装了病毒防火墙软件,也只能识别绝大部分已知的病毒,对相当大的未知病毒并不能识别。