Thì quá khứ hoàn thành:1

Thì quá khứ hoàn thành:
1. Công thức:
(+) ____________
(-)____________
(?)____________
2.Cách dùng:
-____________________________
-Dấu hiệu:_______________________
- My first time i make a question in this web, if there was a problem in the question or something, plsss don't hate or what, you can say it ( that problem) to me, I'm gonna fix it ok?-