单选题
In the disciplines underlying our high-tech economy, America is steadily losing its global edge.
A. border B. superiority C. appeal D. territory
【正确答案】
B
【答案解析】edge：边缘，优势，edge-cutting：先进的；border：边境，界限，边界；superiority：优势，优越；appeal：魅力，诱惑力；territory：领土，活动范围，领地，领域