Complex sentence: The Librarian of Congress is the head of the Library of Congress, appointed by the President of the United States with the advice and consent of the United States Senate, and serves as the chief librarian of all the sections of the Library of Congress.
Split into simpler sentences: The Librarian of Congress is the head of the Library of Congress, appointed by the president with the advice and consent of the Senate. He serves as the chief librarian of all the sections of the Library of Congress.