31. The room is in a terrible mess; it _______ cleaned.

Luggage may not be brought into the building ________ a guard has checked it first.

The harder you_______ , the greater progress you______

uld be offered a _____ of $5, 000 forthe arrest of the murdered, according to the news on TV last night.

He went to the station hurriedly only ______that the bus had gone away.