Complex sentence: Ayatollah Marashi Najafi library is the third biggest library in Iran after the Central Library of Astan Quds Razavi and Library of Parliament and is the world's third largest Islamic library.
Split into simpler sentences: Ayatollah Marashi Najafi library is the third biggest library in Iran, after the Central Library of Astan Quds Razavi and Library of Parliament. It is the world's third largest Islamic library.