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
网友回答
A. that it is
B. to be
C. that it has been
(答案→)D. to have been
解析：考查固定句型。It is said that…;或者sth is said to do/be/have been…;根据下面得over the past few years可知应该使用完成时，故D正确。