PAST: PERFECT SIMPLE AND PERFECT CONTINUOUS

PAST
PERFECT SIMPLE	PERFECT CONTINUOUS
Ÿ to talk about actions happened before sth which is described in the past simple ex. When he got to the party, people had already left.	Ÿ talking about sth which happened before sth and it is described in the past simple. Focuses on the length of time ex.  I needed a break because I’d been working for four hours straight.
Ÿ also with typically time expressions (as when, as soon as, after, before…) ex. He bought the car before he had got the driving licence.	Ÿ also to say how long sth happened up to a point in the past ex. She’d been playing for Milan for only two games when she scored her first goal.
Ÿ often with adverbs: already, just, never ex. I had never sailed the seas until I came to Sardinia.