I think _______ our duty to keep our environment clean and tidy.

_______ of us has some bad habits. We must get rid of them.

Roy made several kites, but _____ of them can fly high in the sky.

---I took lots of photos in Hainan.---Really? Could you show ______ to me?

—When shall we meet again?--Make it____ day you like. It’s all the same to me.