第19题: [单项选择]下面的安全攻击中不属于主动攻击的是______。 A. 假冒 B. 拒绝服务 C. 重放 D. 流量分析 参考答案:D 答案解析:[解析] 被动攻击的特点是偷听或监视传送,其目的是获得信息,有泄露信息内容与流量分析。主动攻击涉及修改数据流或创建数据流,它包括假冒、重放、修改消息与拒绝服务。
第33题: [单项选择]{{B}}Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. He’s been in the program for several days. B. He is working hard on the program. C. He works only during the day. D. He will probably never finish. 参考答案:B 答案解析:[听力原文]
M: When is Jack going to finish writing that paper
W: I don’t know. He’s been working on i