Oh, boy, why are you killing your time this way? Can’t you find something ________ doing?
In the film Murder in a Country House, a doctor is found _______ in the house, so the film is _______ horror and mysteries.
The book will_______ you when you need help.
Have you heard that the research he spent most of his time_______ perfect success?
Parents always think_______ easy_______ high scores, but children think it is difficult.
You should guard_______ theft on the bus.