--- Who left the door open? --- Oh, sorry. I _____ the door.
. ____ it will do us harm or good remains to be seen.
. The river, ____ are covered with trees, is very long.
He is rather difficult to make friends with, but his friendship, ____, is more true than any other.
1. — Have you known each other for long? — Not very long, ____ we started to work in the company.
__________ some medals came to live in the sea is not known.