1, yesterday, while i was walking in the park, it started rain.
2, yesterday, while i was listening radio, the phone rang.
3, would you mind if i use your book?
4, would you mind if i turn off the air conditioner?
5, nhi decided to go camping yesterday.
6, nam decided to go to school by bus yesterday.
CHÚC BẠN HỌC TỐT ?!!