Grammar Stuff: Past Perfect

Late last year, I bought a book entitled "Practical English Usage" by Michael Swan. It's one very useful reference book. It's my go-to for a lot of grammar questions. I was told that I don't have to know grammar since that's not the focus of my current company. However, I'm glad that I have the book because I've had a number of students ask some grammar-related questions.

So, on my free time, I've been jugling between Japanese grammar and English grammar. I thought it might be useful to write down some of the things I have trouble with... for easy reference. All these are from Practical English Usage: New International (student's edition Revised) by Michael Swan (ISBN: 9780194420969)

Today, it's about an Aspect I'm often confused about - the Perfect aspect. In particular, the Past Perfect.

Form: had + past participle ( I HAD FORGOTTEN.)

Meaning and Use: Earlier Past
Something had already happened at the time we are talking about.

When I arrived at the club, Jon HAD already GONE home.

Used to talk about things that had happened before the saying/thinking took place:

I TOLD her that I HAD finished... (NOT that I HAVE finished)

I THOUGHT I HAD sent...

Used for unreal events

Used to talk about how long something had continued up to a pat moment.

When they got married, they HAD KNOWN each other for 10 years (NOT... they knew each other for 10 years)