Insomnium Present perfect:
I have already done this exercise.
Have you ever been to London?
I have read this book before.
I haven't done my homework yet.
My mother has gone to the library an hour ago.
Past perfect:
I had read this book, before he told me about it
She had had a rucksack before I bought the same one
They had broken the window before I returned home
I had flown to Spain before he flew
My granny had sung this song before I sang it