Past continuous tense

The past continuous tense is also sometimes called the past progressive.

Here is how to form the past continuous in English.

Structure of past continuous
positive negative question
I was reading a book. 
He/she was talking. 
It was raining. 
I wasn't (was not) reading.
He/she wasn't talking. 
It wasn't raining.         
Was I reading?
Was he/she talking?
Was it raining?
You were reading a book. 
We were waiting. 
They were drinking. 
You weren't (were not) reading.
We weren't talking.
They weren't drinking.
Were you reading?
Were we waiting?
Were they drinking?

Past continuous - common mistakes
Common mistakes Correct version Why?
I waiting for him almost two hours. I was waiting for him almost two hours. To form the past continuous we use was/were + ing.
What did he doing when you saw him? What was he doing when you saw him?
We were playing tennis every morning. We played tennis every morning. We use the past simple for repeated actions in the past.
They watched TV when I came. They were watching TV when I came. We use the past continuous when we want to say what was happening (what was in progress) at a particular time in the past.