单项选择题
下列聚合物中,通过缩聚反应生成的是:
未知题型 The boy admires his father and ______ his every word.The boy admires his father and ______ his every word.
单项选择题 He is thoughtfulnd qulified fther; He ____some time every dy to red to his children.sets d
未知题型 郭沫若、宗白华和田汉三人通信集的名称是( )。