Fluctuations of text complexity: the case of Basic State Examination in English Diana Gizatulina, Farida Ismaeva, Marina Solnyshkina, Ekaterina Martynova and Iskander Yarmakeev SHS Web Conf., 88 (2020) 02001 Published online: 24 December 2020 DOI: 10.1051/shsconf/20208802001