As histórias usam os dois passados juntos, como num filme:

• o past continuous pinta a cena: o que estava acontecendo;
• o simple past conta o fato: algo que acontece de repente e termina.

I was reading when the phone rang. — Eu estava lendo quando o telefone tocou.

A cena: was / were + -ing	O fato: simple past
We were walking home…	…when it started to rain.
Marina was cooking…	…when Bidu came into the kitchen.
I was having a shower…	…when Luana called.

Palavras novas: to ring — tocar (telefone, campainha), passado rang; suddenly — de repente; bookshop — livraria (atenção: library é biblioteca).