Studying hard is the right way to lead us __________ success.

People read newspapers and magazines in order to keep themselves _____ of what is going on in the world outside.

_______ medicine works in a human body is a question _______ not everyone can understand fully.

Must we keep the window _______ all the time —No, you don’t have to.

stayed awake in bed, watching the heavy rain beating ________ the windows.