-- _____is that used for?---_____ the floor.
My MP4 has disappeared. Who _______ have taken it away?
The government has taken some measures to solve the shortage of electricity, but it may be some time ______ the situation improves.
He reminded me that the poor weather may have ___ the small crowd.
I have no idea ___ David is in trouble, he will turn to you for help.
Who do you think Mr. Brown had ___ within three months?