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
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。