1)become 通常用作联系动词,同amisare一样,如my face becomes red , 同样的词还有get, turn, 等,如it turns cold天变冷了.absorbed是过去分词做表语,相当于形容词.如excited, interested,gone,disappointed,worried,等很多的.如:i am interested in english. the boy is gone when i came here. they are excited about the news.
2)两个大句子是并列句,第一个又是由when引导的时间状语从句.