高二英语下学期Unit16TheUnitedStatesofAmerica课件

Unit 16The United States of America Reading The American south 形式 动词不定式 动名词 / 现在分词 时态 主动 被动 主动 被动 一般时 进行时 完成时 完成 进行时 to do to be done to be doing to have done to have been done to have been doing doing having done being done having been done，