前面有after 或者before 的现在分词问题

Question

前面有after 或者before 的现在分词做状语， 后面直接加ving ,还是 having done
having studied english for yrs after having studied english for yrs , after stuying english for yrs ,前面如果已经有了after 或者when , before 的话后面是不是直接加ing 就可以了？？

Answer 1

你好。
一般来说：
1 having studied english for yrs （分词结构）==after studying english for yrs (介词+动名词结构)

2 before he came,he phoned me first (时间状语从句结构)===before coming(介词+动名词结构),he --- - .

注意：
after / before 在这里是介词，不是连接词。when,while永远是连接词。追问

那after having studied english for yrs 呢

追答

你好。这是“介词+动名词”的结构==after he has / had studied English for years,- - - .（时间状语从句）

追问

不在乎语法，就是这句话可不可以这样写，可不可以这样翻译

追答

完全可以，You are right and quite accepted

Answer 2

没错它们都是连词afterbefore不能跟done