请高手回答 ing+过去分词放句首的用法

题目

请高手回答 ing+过去分词放句首的用法
刚刚看玩了,分词放句首做状语的用法.
但是有时遇到,Having +过去分词,+句子.
或则Having been +过去分词
这是什么用法,或则什么语法
麻烦高手详解有例子
说实话1楼的虽然只是句子还好理解，2楼的什么完成被完成的，没句子很抽象

答案

分词位于句首作状语时,其逻辑主语都是这个句子的主语.
例：Finishing his homework,he went out for a walk.
完成作业后,他出去散步了.
至于“Having +过去分词+句子,Having been +过去分词” 的句子,其用法都是相同的,只是强调的角度不同而已.单独用分词时,只强调动作的完成,不涉及对“现在”的影响,而用“Having +过去分词+句子,Having been +过去分词”时,就必须涉及到“现在”,也就是现在完成时的基本用法.
例：Having seen the film,he felt very excited.
Having been living in this city for a month,he visited many places of interest.
当然,如果是过去分词（短语）作状语,则含有被动意义.
例：Hit by a car yesterday,he he had to be in hospital.
Watered by my grandmother,the flowers in the garden look more beautiful.