Complex sentence: Its replacement, an elementary-only brick structure, was constructed in 1945 and is still in use; known as the Ashburn Annex, it is a training center for the LCPS district and has also been used for Broad Run High School population overflow.
Split into simpler sentences: Its replacement, an elementary-only brick structure, was constructed in 1945 and is still in use. Known as the Ashburn Annex, it is a training center for LCPS and has also been used for Broad Run High School population overflow.