问题
选择题
AIDS is said ______ the biggest health challenge to both men and women in that area over the past few years.
A．that it is
B．to be
C．that it has been
D．to have been
答案
答案：D
句意：据说，在过去的几年中，艾滋病对于那个地区的男女来说已是最大的挑战。It is said to do / to be doing / to have done的形式。由此可淘汰A和C两项，由于句子的时间状语over the past few years要用完成时，所以淘汰B项。