Respuestas
Esta es la estructura del pasado continuo (afirmativo):
Sujeto + was/were + verbo + -ing.
Según en sujeto, se usará was o were.
She, he, it, I = was
We, you, they = were
1. was doing
2. were having lunch
3. was working
4. were playing
5. was using
6. was taking
7. was sleeping
8. were preparing
9. was singing
10. were washing
Respuestas:
1. I was doing my homework when the teacher arrived.
2. We were having lunch at 1 p.m.
3. My mother was working when her cellphone turned off.
4. The students were playing basketball when it started to rain.
5. The teacher was using the computer all the morning.
6.I was taking a shower when my father arrived.
7. My dog was sleeping in the sofa when I called it.
8. They were preparing a special meal at 5 p.m.
9. My sister was singing an English song.
10. We were washing the car when the accident happened.