关于一个英语长句的成分分析不明白了,
句子,most people seem to have more bad dreams early in the morning ,progressing toward happier ones before awakening,suggesting that they are working through negative feelings genarated durling the day.
整个句子的翻译我也知道啊,就是不太清楚这个句子的结构到底是怎么样的?里面有两个逗号,逗号后面各有一个ing形式的动词开头,它们分别构成句子的什么成分呢?为什么用ing形式,不用ed的形式呢?