Fill in the Blanks (Reading & Writing)

Regional airports often struggle to remain —viableviablyviabilityviables once major airlines withdraw their routes. Local authorities argue that these smaller hubs —sustainsustainedsustainingsustainable rural economies by connecting remote towns to national markets. Without public subsidy, however, many such airports risk —closingcloseclosedto close within a few years, leaving communities more —severelysevereseveritysevered isolated.