CAMBRIDGE – Retired Gen. Colin Powell, a former Secretary of State in the George W. Bush administration, addressed a packed audience at Harvard on the subject of education in the U.S. on Monday.Powell described himself as once heading up a school system of his own, in the U.S. armed forces: a group of young people whose ages ranged from “17 to 20-something,” he said.?Some of them had difficulties in life,” he said. “I was a teacher, trainer of men and women.”These days, education is very much on Powell?s mind through his role with the America?s Promise Alliance, a network of over 400 organizations whose work includes helping students graduate high school “ready for college, work and life,” according to the America?s Promise website. Powell is founding chairman of America?s Promise; his wife, Alma, is the current chair and their son Michael is on the board. America?s Promise got its start 15 years ago after Powell chaired a summit in Philadelphia attended by then-President Bill Clinton and former presidents Gerald Ford, Jimmy Carter and George H.W. Bush, and former First Lady Nancy Reagan.?We?ve got our work cut out for us,” Powell said.Powell, who recently turned 75, spoke to a crowd at the Harvard Graduate School of Education. He is also in town to deliver the commencement address at Northeastern University.Wednesday, he mentioned challenges current students face: “thousands of schools that are dropout factories,” a dropout rate that has hovered between 25 and 33 percent, and higher dropout rates for minority students. He also noted that of the 17-to-24-year-old age cohort “where we recruit soldiers, sailors, airmen and Marines, 70 percent can?t get in the Army,” for reasons including “no high school education or a weak high school education,” as well as “obesity or a criminal record.”Powell said that family members provide the first imprint on a child?s education, and perhaps the most lasting one.?Education begins the moment a child in its mother?s arms hears its mother?s voice and knows it?s his mother?s voice,” he said.He added, “If there?s love in the home, if a child sees love in the family, warmth in the family, kindness in the family, the child will identify that with good, and that?s the route the child will take.”