You’d better walk _______ the footbridge. The shopping mall is on the other side of the street. [ ]

It is reported that the United States uses ______ energy as the whole of Europe.

It was not until he came back _____ he knew the police were looking for him.

一What’s behind door? I can’t open it．一Let me see．Oh,there’s a chair．

Thanks for____ me about your morning.