The rate of racial progress varies in different areas of the country, but in the past ten years more improvement.
A. there is
B. it is
C. there have been
D. there has been
网友回答
A. there is
B. it is
C. there have been
(答案→)D. there has been
解析：考察时态。In the past ten years与现在完成时连用，结合句意可知D正确。句意：在过去十年中，已经有了更多的进步。