Question

AIDS is said_______ the biggest health challenge to both men and women in the earth over the past four years.

A．that it is

B．to have been

C．that it has been

D．to be

Answer 1

B

解析試題分析：考查固定句型。sb/sth is said to do sth據(jù)說某人/某物做了某事，當兩個動作發(fā)生有先后關系時，用不定式的完成時，即to have done。句意：在過去的四年里，據(jù)說艾滋病已經(jīng)是威脅男性和女性健康的最大的因素。over/in the past... years“在......過去的幾年里”，常與現(xiàn)在完成時連用，關系B。
考點：考查固定句型和時態(tài)