Question: when does the champions league round of 16 start
[{'answer': '13 February'}, {'answer': '13 -- 14 & 20 -- 21 February 2018'}, {}, {'provenance': [{'wikipedia_id': '54326299', 'title': '201718 UEFA Europa League knockout phase', 'section': 'Section::::Round of 16.\n', 'start_paragraph_id': 40, 'end_paragraph_id': 40, 'meta': {'evidence_span': ['February 2018, 13:00 CET.', 'CP won 64 on aggregate." "Arsenal won 42 on aggregate." "Marseille won 31 on aggregate." section begin=R16 / The draw for the round of 16 was held on 23 February 2018, 13:00 CET.section end=R16 / section begin=R16 / The first legs were played on 8 March, and the second legs were played on 15 March 2018. "Lazio won 42 on aggregate." "RB Leipzig won 32 on aggregate." "Atlético Madrid won 81 on aggregate." "\rhighlight sentence(s) containing evidence, not only the answer']}}]}, {'provenance': [{'wikipedia_id': '54326299', 'title': '201718 UEFA Europa League knockout phase', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The 201718 UEFA Europa League knockout phase began on 13 February an', 'The 201718 UEFA Europa League knockout phase began on 13 February', 'The 201718 UEFA Europa League knockout phase began on 13 February and ended on 16 May 2018 with the final at the Parc Olympique Lyonnais in Décines-Charpieu, France, to decide the champions of the 201718 UEFA Europa League. A total of 32 teams competed in the knockout phase. Times up to 24 March 2018 (round of 32 and round of 16) are CET (), thereafter (quarter-finals and beyond) times are CEST (). The schedule of the knockout phase was as follows (all draws\rhighlight sentence(s) containing evidence, not only the answer']}}]}]