Long after D.C. public school bells signaled the end of classes yesterday, hundreds of teachers were still working last night at the first citywide teachers' convention.

Drug activity in the schools, absenteeism and teen-age pregnancy were at the top of lists of concerns among many of the teachers and principals.

Some said they were concerned with helping the city's 80,000 public school students raise their ambitions, while others said they are seeking ways to help overcome the effects of poverty that leave many city pupils at a disadvantage.

The D.C. school system's first ever teacher convention is intended to offer teachers information about state of the art technology and new strategies to attack chronic problems in the schools, officials said.

But in a keynote address, School Board President R. David Hall dispelled any notion that quick-fix solutions would come out of the convention.

"The struggle will be won, not by new strategies, new approaches or better materials," he said. "We must recommit ourselves . . . to overcome the negative influences of society" that affect students.

"We have to reach within ourselves and bring up a new measure of excellence . . . Failure will never overtake us if our will to succeed is strong enough."

The convention features more than 100 exhibitors from publishing companies, computer firms and educational resource organizations as well as workshops on various topics, including teen-age pregnancy, suicide prevention and drug abuse.

The two-day event at the D.C. Convention Center was designed to attract some 6,000 teachers, students, administrators and exhibitors. Participants said they have come to share ideas and problems of the profession and to shop for textbooks, computer equipment and other teaching materials.

Among those who addressed the gathering were board President Hall, Superintendent Floretta McKenzie, Mayor Marion Barry, Del. Walter Fauntroy (D-D.C.), President William Simons of the D.C. teachers union and D.C. Congress of Parents and Teachers President William Brown.

McKenzie said in an interview that school officials are not ready to offer teachers and principals new ideas, only new hope.

"We're counting on teachers and principals to do the job for the children," she said. "We're counting on them and we want them to know that."

James A. Williams, principal of Cardozo High School in Northwest Washington, said encouragement is always appreciated but he suggested that the school system begin to look at new ways to deal with the serious problems students face each day.

Clemmie Strayhorn, principal at Spingarn High School in Northeast -- where the Rev. Jesse L. Jackson convinced 100 students to admit to using drugs last week -- echoed Williams' remarks.

"We're in the business of helping people," Strayhorn said. "I think we're doing a tremendous job of doing that but a lot of students are alienated.

"They don't see themselves ever becoming president of the United States or president of a large corporation or even principals, doctors or lawyers. Many of them are just preoccupied with survival -- day-to-day survival."