单选题 19.A rogue loose called a hacker could take control of the entire system by implanting his own instructions in the software and then he could program the computer to erase any sign______.
【正确答案】 C
【答案解析】分析本题可知，空格处的主语是动名词，所以此处应该用名词与代词的所有格形式，并且动名词所表达的事件应先于被修饰词，应用动名词的完成时形式。由此可知本题答案为C。