1. PAST PROGRESSIVE VERBS
Anytime you see “progressive” or “continuous” it always means “be+verb+ing”.
Since it’s the past we form it using the past form of “be”. Like this:
I was visiting
We were playing
You were not listening
You were sleeping
He/She/It was eating
They were asking
We use “progressive” tenses to talk about something that took a long time.
Most of the time, you can use simple past. But this emphasizes that it took a long time to complete the action.
Yesterday, I ate a hamburger.
Yesterday, I was eating a hamburger all afternoon.

2. PAST PROGRESSIVE VERBS
To make questions and negative sentences you need the helping verb “be” in the past tense (which is “was/were”):
Questions (Were/Was…?):
Negatives (wasn’t/weren’t):
Were you playing basketball?
Was he bothering you?
I wasn’t watching TV.
We weren’t speaking Chinese.

3. PAST PROGRESSIVE VERBS
The most common usage, though, it when it hugs another action.
(That is, when it happens before and after another action)
(1) It can be before and after a specific time.
(2) It can be interrupted (another action happens in the middle to stop it).
This type of sentence is very common, but requires a word to combine the two clauses (the past, and the past progressive).
At 8PM yesterday, I was watching TV.
(You watched TV before and after 8PM)
I was watching TV, when the phone rang.
(You watched TV at the time the phone rang and stopped)

4. PAST PROGRESSIVE VERBS
We use “when” and “as” to combine the past and past progressive clauses. These clauses can go in any order.
But “when” goes with the past progressive clause,
while “as” must go together with the past tense clause.
I was eating a hamburger, when I saw a cockroach.
As I was walking to school, I was hit by a car.
When I was in Korea, I was speaking Korean.
I heard a scary noise, as I was going to sleep.

5. PAST PROGRESSIVE VERBS
The most common usage, though, it when it hugs another action.
(That is, when it happens before and after another action)
(3) When you do two things at the same time.
To combine two clauses that happened together, we use “while”.
We can use “while” with either the first clause, or the second clause.
I was listening to music, while I was doing my homework.
(You listened to music and did homework together)
He was cheating, while he was doing his test.
We were listening, while we were doing our homework.
While I was checking you work, I was correcting mistakes.

6. PAST PROGRESSIVE VERBS
When we talk about interrupting actions,
the interrupting action is always past tense.
NOW
broke my arm
play hockey
When I was playing hockey, I broke my arm.
NOW
fall asleep
watch TV
As I was watching TV, I fell asleep.