Question

 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 is has been                                            D. to have been

Answer 1

解析：选D。It is said that+主语=主语+is said to do/have done; 由时间状语可知应用现在完成时。

独具【方法技巧】人或物+be said后的“多样化”不定式

在此结构中，主语不可以是形式主语。

1

 不定式的一般式。该形式根据需要可用主动或被动式，表示两种情况。

(1)表示不定式所表示的动作尚未发生或将要发生。

He is said to go abroad soon. 据说他不久要出国。

(2)表示一般情况(尤其是当不定式表示状态而非动作时)。

The tigers are said to be endangered.

据说这些虎处于濒危状态。

2

 不定式的完成式。表示不定式所表示的动作已经完成。该不定式根据需要可选用主动或被动式。

This book is said to have been translated into several foreign languages. 据说这本书已被译成好几种外语。

3

 不定式的完成进行式, 强调不定式所表示的动作迄今为止已经持续了一段时间。

This film is said to have been going on for two months now. 据说现在这部电影已经连续上演两个月了。

4be said+不定式的进行式, 表示不定式所表示的动作正在进行。

They are said to be researching into the question.

据说他们正在研究这个问题。