Past Continuous - Quá khứ Tiếp diễnFORM of Past Continuous
S + was/were + V-ing
I was learning English.
He was swimming well.
They were watching TV.
S + was/were + V-ing
I wasn't learning English.
He was not swimming well.
They weren't watching TV.
Was/Were + S + V-ing ?
Was you learning English?
Was he swiming well?
Were they watching TV?
Use the Past Continuous to indicate that a longer action in the past was interrupted
by another action or event. In other words, it expresses an unfinished or
incomplete action in the past.
 I was walking on the street when it rained.
 While I was painting a picture, she came.
 They were playing tennis at 10.00 yesterday.

USEs of Past Continuous
1. to describe an ongoing action that was interrupted by another event or
action:
 I was watching TV when she called.
 When the phone rang, she was writing a letter.
 While we were having the picnic, it started to rain.
 What were you doing when the earthquake started?
 I was listening to my iPod, so I didn't hear the fire alarm.