You should keep your eyes _____ when you do eye exercises.

Many visitors come to Beijing because it is ________ city.

Tell me about Brother Sharp, please. — He was a beggar(乞丐). He became a blue-eyed boy(红人) on the Internet because of his cool appearance and dressing style.

Great changes _______over the years．

Mr. West showed me around the library ______he was working. [ ]