The sentence veía la tele cuando llegó mi amigo (I was watching television when my friend arrived) is a good example ... imperfect tense in Spanish why not explore regular verbs in the preterite ...

The Spanish preterite tense is used to describe completed actions in the past. For example: Fui al cine ayer. - I went to the cinema yesterday. Viajamos en tren. - We travelled by train.