past progressive - the continous form of the past
The past progressive is the continous form of the past and is used when an action is done in the past over an undefined period of time.
Often times people express themselves in the past progressive if an action is spread over an undefined period of time and nothing noteworthy happens:
I was playing basketball yesterday. = Meaning: while I was playing basketball nothing special happened.
The progressive form of the past uses the suffix -ing. Apart from that the same rules apply as in the present progressive.
The negation simply adds not to the auxiliaries was and were, the short forms are accordingly wasn't and weren't.
The question puts the auxiliary to the front of the sentence. (inversion)