having done 和 doing在独立主格结构中的区别

having done 和 doing在独立主格结构中的区别 独立主格结构的done 和 being done having done和doing在句首的区别? having done ,和 doing having done 与doing 区别 独立主格结构中,独立主格和句子中的时态要不要求一致或相近? regret doing和regret having done 有什么区别 regret doing sth 和 regret having done的区别 having done和doing做分词的区别? regret doing和regret having done有何区别 关于done和having been done在非谓语中的区别 在英语语法中,悬垂现象和独立主格结构有什么区别