听力原文： City officials have approved a plan to offer illegal immigrants identification cards that would let them open bank accounts and use other services that may be unavailable without driver's licenses or state-issued IDs. Supporters say the program, approved by the Board of Aldermen and believed to be the first of its kind in the nation, will help safeguard the city's estimated 15, O00 illegal immigrants, If they can open bank accounts, immigrants will be less likely to carry large amounts of cash, a practice that makes them easy targets for robbers. Monday's approval stands in contrast to new laws or proposals in more than 90 cities or counties around the nation prohibiting landlords from leasing to illegal immigrants, penalizing businesses that employ them or training police to enforce immigration laws. What is the plan mainly about?