There is such a thing as too much time off from school. The Daniels sisters -- Tori, 10, and Haley, 7 -- attend Indian Head Elementary. They played video games and romped in the snow last week after the winter storm kept Charles County students out of classes for three days.

But they also grew bored. And constantly fought with each other, in the thin-line-between-love-and-hate way that made things a little more noisy in their Pisgah home.

It was more than Valerie Daniels, 33, was used to. She is a stay-at-home mother. "There's been no piece and quiet," she said. Her children smiled.

Daniels stood outside Indian Head Elementary on Friday morning, about to drop the girls off for school. Students in Charles and Calvert counties returned to classes Friday; students in St. Mary's went back Thursday. All three districts opened with a two-hour delay.

Southern Maryland represented three of the nine public school systems in the state that were open for classes Friday. Several other Washington-area suburban districts -- such as Montgomery, Prince George's, Howard and Anne Arundel counties -- and schools in Virginia remained closed all week and were scheduled to reopen tomorrow.

Calvert school officials reported that the reopening went smoothly. Brian W. Stevens, director of pupil transportation in Calvert County, said county and state highway department crews worked quickly to clear about 40 problems areas the day before school was set to reopen.

In St. Mary's County, where total snowfall was less than areas to the north, J. Bradley Clements, chief administrative officer, said his staff inspected roads and cleared snow from around schools and on building roofs, and deemed the schools ready to open Thursday.

The snow days bring myriad changes and disruptions to deadlines and curriculum plans. Charles school officials told parents of middle and high school students to expect their children to bring home interim reports this Friday, instead of last Friday.

At the drop-off curb outside Indian Head Elementary, the familiar thump of a car door closing could be heard again and again Friday morning. In the chilly damp air, Principal Gregory Miller greeted parents and children while art teacher Kathleen Brown stood at the front door to welcome students back.

Attendance was lighter than normal. Charles County public schools spokeswoman Katie O'Malley-Simpson said that nearly 12 percent of the 24,000 students were absent Friday. A week earlier about 6 percent of students were absent, officials said.

Jade Dyson, a 10-year-old fifth-grader, was elated to be back. She spent this week at her grandmother's house, the lone girl among a brood of male cousins and her younger brother.

"I couldn't stand another day with all of them," she said.

But fifth-grade teacher Priscilla Caporaletti questioned the opening. Caporaletti, who lives in Waldorf, said she had to swerve her car on her drive to work to avoid hitting students walking to school in the street because the sidewalks were packed with snow.

"It was too soon," she said.

Caporaletti and fifth-grade teachers Anne Murphy and Joanne Gerber said they were altering their lesson plans Friday. They also will have to shift things around this week because they now have less time to prepare for the Maryland School Assessment, the new state test scheduled to be given in grades 3, 5, 8 and 10 beginning one week from tomorrow.

Gerber said that although it was a shortened school week and Friday was an abbreviated school day, students who were absent would be a day behind.

By noon, just an hour after school had opened, the silent hush of learning took over. Students were working at their desks, raising their hands in class or busy with assignments.

"There is teaching that is going on, and there is learning that is going on," Gerber said. "The kids who are not here are going to have to play catch-up."

Anne Murphy, a fifth-grade teacher at Indian Head Elementary, checks roll Friday. Above, cars line up to drop students off at Indian Head on the first day of school in week of cancellations. Charles and Calvert were among nine area school systems to reopen Friday; St. Mary's schools resumed Thursday.Valerie Daniels and her two daughters, Haley, left, and Tori, behind her, walk from their car to Indian Head Elementary School on Friday, students' first day back in Charles and Calvert.