There is no _________ that the Chinese people will present to the world a successful, splendid and unforgettable exposition（博览会）.

___you ___the window?—Yes, I am.

While you are having an exam, you must write as ________ as you can.

Sam spends half an hour_____ TV every day.

There is _____ “s” and _______ “c” in the word “school”.