Past continuous tense
The past continuous describes actions or events in a time before now, which began in the past and is still going on at the time of speaking. In other words, it expresses an unfinished or incomplete action in the past.
Signal words
Past Progressive
all day long yesterday,
at this time yesterday,
at \(6\) o'clock yesterday               
1. an action going on at a certain  
period of  time in the past                                                   
I was riding my bike all day long yesterday.
I wasn't watching TV at 6 o’clock yesterday.
Were you eating breakfast at \(7:00\)?
2. parallel actions happening at
the same time 
I was studying while 
mother was making dinner.                              
be (was, were) + verb + ing = past continuous/progressive.

Short form of auxiliaries: wasn't, weren't = was not, were not
The past progressive tense functions:
1. continuing action, something that was happening, going on, at some point in
    the past.
I was riding my bike all day yesterday.
2. a limited duration of time while something else was happening.
He lost his watch while she was running.
3. incomplete action
I was sleeping on the couch when mother came in.

4. an action that is inconstant but habitual in nature.
My father was always lecturing my brother.
5two parallel actions happening at the same time (in the past).
I was studying while mother was making dinner.
Spelling rules:
a) if the syllable is stressed we double the last consonant and then add -ing.
commit - committing
swim - swimming
run - running
b) if the syllable is not stressed we don't double the last consonant.
open - opening
c) If the base verb ends in ie, change the ie to y.
lie - lying
die - dying
d) If the base verb ends in e, omit the e.
come- coming