ていた

The ていた form shows that an action was in progress in the past or a past state that continued for some time. It emphasizes the ongoing nature of the action or situation before another event or moment in the past. It can set the scene or background information. Often is used when you want to describe what someone was doing when something else happened, or simply to recall a past activity you were engaged in. Examples: - 雨が降っていた。 It was raining. - 私は窓の外を眺めていた。 I was looking out the window. - 電車を待っていた。 I was waiting for the train. - 彼はその本を読んでいた。 He was reading that book.