It will take a long time for the effective use of natural resources _________.
She wrote a month ago, ______ we’ve heard nothing.
I have a lot of books, half of ______ novels.
The old house, in front of _________ there is an apple tree, is _________ I used to live.
Houston Rockets, ______ led by as many as 10 points in the first half, has dropped three straight after winning eight matches.
Is this hotel _____ offered you a job ______ you stayed the first time you arrived here?