D

a) Yes, I did

b) Yes, I did

c) I used to go to my grandparents' house

d) I used to play badminton, hide-and-seek, ect...

e) My grandparents used to live in On Luong village, Phu Luong district, Thai Nguyen Province

f) No, he didn't

g) Yes, she did

h) Yes, she did

i) They used to go school on foot

Bác Hồ.