22. The computer programs are a puzzle to me. The more I think of them, the more questions I think of .
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, ________?