1.   He challenges stereotypical ideas about people with disabilities.

2.   Now these are very challenging ideas.

3.   An officer in the local chapter of Sons of Confederate Veterans, Powell has spent his adult life challenging the idea that the Confederacy was only about slavery.

4.   And he challenged the idea that the two companies were all that different.

5.   And Oberg challenged the idea that the recent problems on Mir are a natural cost of making progress in space.

6.   Brooks also challenged the idea that men are biologically programmed toward violence, or hard-wired for sexual deviance.

7.   But a study led by Lee Katz at Yale is challenging the idea that women are the more subcutaneously-challenged sex.

8.   But Fire Commissioner Howard Safir challenged the idea that the reliability of public telephones was an essential element in his plan to remove the alarm boxes.

9.   But he challenged the idea that the administration was standing up for anti-democratic forces in Peru.

10.   But Martin and several others challenged this idea on the ground that protoarchaeopteryx apparently lived later than archaeopteryx and could not therefore have been its ancestor.