1. Mai is a friend of mine.

a+ N of dtsh 

2. They will have a group call between 7 a.m. and 9 a.m. tomorrow.

between sth and sth: ở giữa ... và ... 

3. Hoa said that she would do that work for me the next day.

S + said + (that) + S+ V (lùi thì)

will --> would 

tomorrow --> the next day / the following day 

this --> that 

4. While they were watching a science fiction film about UFOs, the phone rang.

While + QKTD, QKD

Hành động đang diễn ra thì có hành động cắt ngang 

5. Nam asked Nga what planet she wanted to visit.

S + asked  +O + Wh + S+ V (lùi thì)

HTĐ --> QKĐ

`color{orange}{~MiaMB~}`