While pulling into Grand Central Station in New York City recently, I saw a warning posted on a train's door: "Watch the gap" — a reference to the space between the car and the platform, a gap wide enough for a passenger to step into and be injured.

Plenty of other gaps also pose dangers in our society: gaps between employers' needs and the skills in the marketplace; gaps in the opportunities available to Americans who speak English fluently vs. those who cannot; gaps created by misunderstanding, suspicion and fear.

In his State of the Union address, President Bush noted the gap between the workforce skills needed to enhance local markets and many local workforces' current skills. He also recognized community colleges' enormous importance in closing that gap.

To remain competitive, U.S. industry needs to improve its productivity continuously, using new tools that require a skilled workforce. Community colleges, because of their flexibility and their ethos of developing partnerships with the business community, are the institutions best suited to help workers acquire new skills quickly.

Community colleges help businesses of all sizes close the gap between Wall Street and Main Street. New Jersey's Bergen Community College, for instance, has a small-business-development center that hosts seminars and offers free counseling to entrepreneurs on finance, marketing and management. Other practical programs:

Technology. At my college, students are learning the Linux operating system (an alternative to Microsoft), engineering and database design for Oracle productivity software and Cisco Systems' computer networks — skills that our market-research and business partners say are essential to the regional economy and are in scarce supply. This will reduce the need for many employers to look for these skills overseas.

Health care. Community colleges, often in association with hospitals, are the primary educators of registered nurses at a time when those professionals are in high demand. In upstate New York, Rockland Community College and Nyack Hospital have one such partnership. The college provides training programs to improve the skills of the hospital's clinical nursing staff.

Industrial maintenance. In Illinois, a longstanding alliance between Danville Area Community College and ThyssenKrupp Gerlach, an international automotive supplier, enables workers at the company's four area plants to earn associate's degrees in industrial maintenance in one-year "fast track" programs.

English proficiency. High on Bush's agenda is the divide between the opportunities available to citizens and resident aliens, and the exploitation often experienced by the nation's illegal immigrants. With the president's recent proposal of a resident-worker program, undocumented immigrants need language and workforce skills to help them better assimilate into society. Community colleges are the vanguards in providing English literacy courses and teaching English as a second language. My college, working with other colleges and the Hispanic Educational Telecommunications System, is creating a virtual campus offering courses to Spanish-speaking students who might not otherwise have access to higher education.

Emergency preparedness. Community colleges are closing the gaps in preparedness so that we are more apt to be ready if another terror attack such as 9/11 occurs on U.S. soil. Experts on many community college campuses are working in partnership with federal agencies to train first responders in corporations and neighborhoods. Kirkwood Community College in Iowa, a leader in disaster training, is constructing a high-tech facility to serve as a center for disaster training and planning.

Cultural cohesion. Perhaps the largest and most dangerous gaps in our society are the cultural ones. We are divided by fear, misunderstanding and prejudice. Community colleges, however, are great multicultural institutions, where people from different nations and backgrounds, speaking different languages and having sometimes vastly different customs come together to learn.

As we travel into the future, it is critical to "watch the gap" — be it economic, linguistic or cultural. With the help of community colleges, those gaps can be bridged.

Antonio Pérez is the president of Borough of Manhattan Community College in New York City.