Dillon Brewer, a student at Park Elementary School in Holbrook, was excited to arrive at school with his Valentine’s Day box ready to be filled with cards and treats, but he probably wasn’t as excited as most students were to learn that they will have a four-day weekend. Holbrook schools will be closed on Monday and Tuesday, Feb. 21 and 22, in observance of President’s Day and to use up an unneeded snow day that was built into the school calendar at the beginning of the year.