The unemployment rate(失业率) in this city ____ from 6% to 5% in the last two years.

问题描述:

The unemployment rate(失业率) in this city ____ from 6% to 5% in the last two years.
A.has fallen B.had fallen C.is falling D.was falling怎么选,什么时态

B
失业率在过去两年里已经从6%降到5%了