$15. For many years, people __ electric ears. However, making them has been more difficult than predicted.[$来源:$Z_xx_k.Com]$
参考答案
B
2010_浙江卷 (英语)
$15. For many years, people __ electric ears. However, making them has been more difficult than predicted.[$来源:$Z_xx_k.Com]$
B