The implication of a perfect tense

I think when someone says "I have/had read a book", it means he/she has/had finished reading it.

nkspbDo they strictly imply that I finished the whole book?

Yes. They both imply starting and finishing the book. That's why, in the second case, I imagine it was a very short book.

CJ

Thanks you for your answers. I'd like to make a clarification, please.

If to use a simple the tense:
"I read a book before he came" - this sentence doesn't strictly imply the completion of the book? As I see, only perfect tenses do. Correct?

Thanks.

nkspbI read a book before he came.

This one, with the simple past, also implies the completion of the book.

nkspbonly perfect tenses do.

No. You've got that wrong. The simple past implies completion just as much if not more. The idea of completion does not help to differentiate the simple past from the present perfect.

Yes, its correct. I know very good English. My name is Sparsh Sharma.

AnonymousYes, its correct. I know very good English.

Then why did you omit the apostrophe in it's?

AnonymousI know very good English.

If I were at that level I would say either of the followings:
I speak English very well. Or, I'm very good at English.

Thanks again. So, if I don't want to show whether I completed a book or not, I should use these sentences:

"I had been reading a book before he came"
"I was reading a book before he came"

?

CalifJimThe simple past implies completion just as much if not more.

By saying completion do you mean just stopped reading or finished the whole book? I

Sorry, I seem not to have read the answer properly. I see you meant full completion I have no "edit" button for some reason.

nkspbif I don't want to show whether I completed a book or not, I should use these sentences:"I had been reading a book before he came""I was reading a book before he came"

Exactly. The -ing forms are best for showing incomplete action. Both of those are good for what you want there.

nkspbBy saying completion do you mean just stopped