第5题: [单项选择]{{B}} Passage One
Questions 26 to 28 are based on the passage you have just heard.{{/B}} A. Use of copper conductors. B. Use of plastic insulator (绝缘体). C. Use of silicon (硅) semiconductors. D. Elimination of chemicals. 参考答案:C 答案解析:[听力原文]26-28
The use of silicon is basic to the developments which have taken place since the 195