<p>1) more than forty years ( have passed ) since a quarter of a million people marched on washington d.c. ( in an attempt ) ( to secure ) civil rights for Black Americans . ( answer is (E) i answered it (A) caz as i know that we cannot use present perfect with a specific time ami right ?))</p>
<p>2) Twenty Five years ( after ) Alex Haley's Roots ( stimulate ) many people ( to research ) their family histories , new technology has been developed to make the task easier . ( answer is A )</p>
<p>3) The telivision station ( has received ) many complaints (about) the clothing advertisements , ( which some ) viewers condemn ( to be ) tasteless ( answer is D )</p>
<p>4) she was concerned about how Hank woul react to the incident , but ( in searching his face , he didnot seem to be ) at all embrassed . ( answer :- a search of his face showes that he seemed not )</p>
<p>5) The Empire State Building , The Sears Tower , the Canadian Ntional Tower - each ( of these structures ) ( was ) the ( tallest ) int the world at the time ( they were ) built . ( Answer:- e but i answer it (a) caz as i think that each should take a singular noun and singular verb , so isn't these a reference disagreement in number ? ) </p>