After 10 months of heated discussion, the Montgomery County school board this week approved by a 4-to-3 vote a controversial new senior high school policy.

The policy, which will become effective in July, calls for four-year high schools with semester-long courses and full-day programs for all students. Some Montgomery high schools now are three-year schools, with senior students allowed to take light course loads and some courses running two semesters.

Board President Daryl Shaw and members Blair Ewing and Elizabeth Spencer continued to oppose the policy, which was tentatively approved last August by the board's conservative majority.

Two of the most hotly debated aspects of the new policy -- tighter attendance requirements and standardized final exams -- were modified in accordance with recommendations by superintendent J. Edward Andrews.

Under the new policy, high school students will lose credit for a course after five unexcused absences. Students now can miss 10 percent of a course -- usually nine classes -- before losing credit. Absences may be excused only for illness, death in immediate family, court summonses and religious observances. Principals also may excuse other absences they consider necessary.

An earlier proposal by board member Joseph Barse to lower a student's grade for three absences was dropped.

Andrews convinced board members to experiment for several years with countywide standardized testing in English and math before requiring similar tests in all major subjects.

The board agree to order final exams only in English and math for three years.Departments teaching other subjects such as social studies will be allowed to devise their own tests in each school. These tests will be counted into the students' final grades.Including the countywide English and Math tests in final grades is optional, with school principals making the decision, during the three-year pilot phase.

Board President Shaw remained outspoken in his dislike of standardized testing.

"I think they label students," he said.

Conservative board member Marian Greenblatt, former board president and a staunch supporter of the policy's stricter measures, said she was pleased with the policy as it was adopted.

"This is a major educational thrust for the board," said Greenblatt. "We will provide equity in the high schools and assure parents that the curriculum is being taught. We're also saying we expect students to be in school."