having done在句首的时候是什么意思?如何用?

having done在句首的时候是什么意思?如何用? having done和doing在句首的区别? 请问在高三英语完成句子中,句首什么时候时候用现在分词``过去分词``还有having done ``之类的, having done放句首的时候句子的时态 Having done 做状语 在句中的位置 having done的用法 having done可否作宾语,如try having done sth being done having been done的区别 Having been done ,done的区别 having been done和done的区别 having been done和having done的区别 not having done 和 having not done 的区别