After John stayed in Shanghai for a couple of days, he got the impression______ the city was very fascinating.
Unless ________ to answer questions, the pupils won't talk in Mrs Smith's class.
—Where did you pick up the stamp?—It was at the post office ________ we worked in the summer vacation.
Who ________ that played a trick on the new English teacher?
Where do you think ________ we can buy that bestseller?
There is no doubt that eating organic food will make you healthier, ________?