问题
选择题
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
答案
答案：D
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。