The unwanted e-mail problem can be solved

问题单项选择题

The unwanted e-mail problem can be solved if ______

A．the government takes action

B．a new technology is adopted

C．more people are aware of the problem

D．joint efforts are made and new technology is used

答案

参考答案：D

解析：[分析] 细节题型。见最后一段。选项A、B、C的内容都对，但都不全面：只有选项D(人们共同的努力和新技术的使用)最全面，是答案。