Complex sentence: The Quakers Dozen is the school's most-selective co-ed a cappella group: during the last week of classes before the winter recess, the group greets the community in the morning with holiday music on the Senior Steps.
Split into simpler sentences: The Quakers Dozen is the school's most-selective co-ed a cappella group. During the last week of classes before the winter recess, the group greets the community in the morning with holiday music on the Senior Steps.