Bai 1:
3, I was preparing the lunch.
4, I was playing badminton with my friend.
5, I was doing morning exercises.
6, I was dancing with Tim.
Bai 2:
2, … was cooking dinner.
3, … were walking in Le Loi street.
4, … was studying for the coming exam.
5, … was watching.
Bai 3:
1, didn’t see; was looking
2, met; were going; was going; had; were waiting
3, was cycling; stepped; was going; managed; didn’t hit
Bai 4:
2, were you doing
3, Did you go
4, were you driving; happened
5, took; was not looking
6, didn’t know
7, saw; was trying
8, was walking; heard; was following; started
9, wanted
10, dropped; was doing; didn’t break