The answer is <u>sonó</u>
Yo me duchaba cuando <u>sonó</u> el teléfono.
The verb duchaba is in pretérito imperfecto and matches with simple past (in this case sonó). This pretérito imperfecto describes an action or state in the past, without indicating whether it was completed or not.
The answer to the first one is 1) Las comedias son serias. The answer to the second one is d. Miguel y Yolanda I believe. I hope this helps and I hope I didn't get either of them wrong. They seem about right to me.
