REVIEW OF PAST TENSE

FORM	FUNCTION
SIMPLE PAST -ed, irregular forms (was, had, etc)	Used to describe a completed event, action, or state in the past. It is usually the main tense used to talk about the past.
SIMPLE PAST WITH DID FOR EMPHASIS Did + base form	Used  to describe a complete event, action, or state in the past and is used for emphasis often the contrast
PAST PROGRESSIVE Was/were + -ing Form	Used to describe actions or states in progress at a particular time in the past. It is often used to describe background action (e.g. the weather).
PAST PERFECT Had + past participle	Used to describe a completed event, action, or state that took place before another past event, action, or state. It is used to talk about things that happened before the man action.

WOULD, USED TO, BE + ALWAYS + -ING
FORM	FUNCTION	EXAMPLES
WOULD (ALWAYS/NEVER) + BASE FORM	Used to talk about habits or customs in the past.	Sara would never remember to buy milk on her way home.
(ALWAYS/NEVER) USED TO + BASE FORM	Used to talk about habits or customs in the past, or to express something that was true in the past, but is no longer true.	The wind always to blow really hard in the Montreal.
BE+  ALWAYS + -ING FORM (PRESENT OR PAST PROGRESSIVE)	Used to talk about habits or customs in the present and past.	They are always laughing and joking. He was always singing.

EXAMPLES 

SIMPLE PAST
We crossed the Channel yesterday.
I sometimes walked home at lunchtime.
She played the guitar when she was a child.

PAST PROGRESSIVE
She was sleeping all night long.
Where was Shannon taking care of her baby?
I wasn't resting, I was working!

PAST PERFECT
She had just left the room when the police arrived.
Had you studied English before you moved to New York?
She had never seen a her mom before she moved to Francia.