He smiled politely ________ Mary apologized for her drunken friends.(2012·山东)
The buses, most of _______ were already full, were surrounded by an angry crowd.
When I arrived at the company, the manager ______, so we had only time for a few words.
David is such a good boy _______ all the teachers like.
The thief tried to break away from the policeman who ______ him, but failed.
The factory was built in a secret place, around ______ high mountains.