问题
单项选择题
The ______ in e-mail messages has affected almost every computer around the world and has caused the damage of up to US$1 billion in North America.
A．illness
B．virus
C．weakness
D．attachment
答案
参考答案：B
解析： 电子邮件中的病毒已经感染了全球几乎每台计算机，在北美造成了多达10亿美元的损失。