1.動詞四中表達中的doing（一人）
? A、做一件事：doing“分詞”
? ? ? ? A flying tyger.
? B、做二件事：doing做“進行式”
At half past nine last night, I was doing my homework.
2.一人：have（has、had）
? ? A、時態~助詞
? ? ? ? I have eaten a breakfast now.
? ? B、情態~動詞
? ? ? ? I have to leave。
? ? C、使役~動詞
? ? ? ?
③具有情態動詞特征：have(had,has) to,used to, ought to
④可做情態動詞又可作助動詞：如：shall(should),will(would)[1]
