After doing your homework 中do为什么要加ing

After doing your homework 中do为什么要加ing
After doing your homework 中do为什么要加ing

After doing your homework 中do为什么要加ing
after是介词,介词后面跟动词要用动名词

介词后用动名词
Thanks for helping me.

“After”是介词
介词后加名词性质的词
do的名词性质词，就是“doing”

after后面不加动词