31. -----What do you suppose made her worried? -----_____________ a gold ring.
Could it be in the restaurant in ____ you had dinner with me yesterday ____ you lost your handbag?
If _____ to look after luggage for someone else, inform the police at once.
—It is the first time that I ________ here in Hong Kong. —What great changes!It’s ten years since I ________here last time.
His report was so exciting that it was __interrupted by applause(掌声).
The thief was about to leave the room when the police ______ and caught him.