1.助動詞be(am, is, are, was, were, being, been)的用法(1) be后跟現在分詞構成進行時態。Who is playing theviolin?誰在拉小提琴?She was reading a book then.那時她正在讀書。(2)be后跟過去分詞構成被動語態。He was asked to do the work.有人要他干