Hoàn thành câu với when hoặc while

Bài 2: Hoàn thành câu với when hoặc while.
1. I first met my future husband (when/while)
I was staying in Ho Chi Minh City.
2. (when/while) ......... I was talking to my uncle on the phone, my mom came home.
3. We were playing cards (when/while)
4. (when/while)
........ the lights went off.
John was working, he often listened to music.
5. (when/while) .............. I was in my hometown, power cuts were very frequent.
6. He called me (when/while).............. I was taking a shower in the bathroom.
7. Crystal was very unhappy (when/while) .............things weren't going well for her.