问题
单项选择题
The successful spread of a virus depends on how long it can (74) unnoticed, before its presence is made known by the activation of side-effects. For example, many viruses (75) their code to avoid recognition.
A．interpret
B．open
C．decrypt
D．encrypt
答案
参考答案：D
解析： 译文：例如，许多病毒通过加密自身代码的方式避免被发现和检测。