Since the founding of New China, great achievements have been made in the study of Chinese modern history, but there are still some weak links and even blind spots. For example, the history of ordinary people, the history of ordinary people, including their ideas, behaviors, customs and habits, daily life Life, etc. , did not attract enough attention. Our historical research should focus on the true stories of the people themselves. Only by telling the stories of the people clearly can it be a true modern history of China. This passage is mainly about the study of modern Chinese history? ['Achievements.', 'Problems.', 'Development trends.', 'The key to breakthrough.']