1) At what firm had you been working before you came to our Institute?
2) I didn't know anybody before Petr met me with his friends
3) My friend was very pale when I met him. I understood something had happened to him.
4) When my friend left I understood that I had forgot to return him the book.
Where have you work before you came to the our university?
I didn't know anybody when Peter met me with his friends.
My friend was really poor when I've met him. I saw something have happened.
Whe my friend was left I remembered I forgot to give a book back.