Teorija

We usually use the past continuous to talk about activities that lasted for some time in the past. The actions can be interrupted by something or can be happening at the same time.
 
Duration in the pastWe use the past continuous to talk about actions or situations that lasted for some time in the past. Duration time is unknown or unimportant.
I was watching TV yesterday in the evening.

She was sleeping on the couch.

The dog was barking.
Interrupted actions in progressThe past continuous is often used when one action in progress is interrupted by another action in the past. The past simple is used in such sentences. We usually use 'when' or 'while' to link these two sentences.
I was talking to James when the telephone rang.

While Angelica was playing tennis, the plane crashed.                     
  
When Bob was painting windows, it started raining.
Simultaneous actions in progress We also use the past continuous to talk about two or more activities happening at the same time. We usually use 'when' or 'while' to link the two sentences.
I was watching TV and Barbara was reading a book.

The family were eating dinner and talking.

When Bob was painting windows, Mary was working in the kitchen.
Polite questions
If we want to ask a polite question, we can use the past continuous.
 
Even though the sentences have the past continuous form, they refer to the present moment. Their meaning is similar to the 'could you' sentences, but they are more polite.
I was wondering if you could open the window.
 
I was thinking you might help me with this problem.
Irritation, annoyanceYou can also express irritation over somebody or something in the past.He was always coming late for dinner!