GMAT Sentence Correction (SC) | Re: Along the major rivers that traverse the deserts of

Please find the two links below - which discusses other usages of have been as well - other than the regular usage of "something that started in the past but continues to the present".. or "its effect continues to the present. These are OG problems and even OG explanations conform to these usages.

http://www.beatthegmat.com/og-12-q-73-t38806.html