--What’s this in the blue box? --________is an orange bottle. _______ orange bottle is mine . 

---Are Mr. and Mrs. Wang living alone in the house? ---Yes, they have three sons, but ______ of them live in their own houses.

—__________ have you been in the sports club?—Since the first month I came to the school．

That’s not      picture.      is on the desk. 

—Excuse me, but is that my passport?—Oh, sorry, I took ________ by mistake.