Complex Sentence: A sentence composed of two or more meaning-related clauses that are not structurally contained. According to the above definitions, which of the following is not a complex sentence? ['Although he is very smart and hard-working, but because the interpersonal relationship is not handled well, he finally regrets withdrawing from the game.', "The setting sun poured its last rays of generosity generously on the quiet courtyard, Yang Yang pushed his father's wheelchair and slowly walked on the country road covered with fallen leaves; his father was intoxicated in the rustic atmosphere and exuded The hot light in life, Yang Yang felt the end of some sort of day.", 'Ye Wen juveniles practice martial arts, youths sell martial arts, middle-aged professors teach martial arts, and the elderly support them every day. In addition, he also opened a hotel, and also operated health care for hands and feet.', "New materials are playing an increasingly important role in a country's economic growth rate, industrial structure layout and changes in people's lifestyle."]