---Do you know_______ the books on the shelves? --- Sorry, I can’t count them, because there are _______books.A. a number of; the number ofB. a number of; a numberC. the number of; a number of
— Is the price of the backpack very______? — No, it ______me only twenty yuan.
— Do you like the western food, Li Li? — No, I think the food of our country is______ that of western countries.
— Mum, I’m too thirsty. —How about having some_______?
—Tom, do you know if Sam ________to my party next week? —I think she will come if she________ free.
—Jim, who taught ________Chinese before you came to school? —Nobody. I learned it by _______.