问题
选择题
The two Chinese scientists have made a wonderful discovery, which marks a major _______ in the basic research in the field.
A．reform
B．approach
C．boundary
D．breakthrough
答案
答案：D
题目分析：考查名词辨析：A. reform 改革，B. approach方式，方法，C. boundary边界，D. breakthrough突破，句意：这两个中国科学家做出重大发现，这标志着这个领域的重大突破。选D。
