Has ________ been decided when we are to hold the sports meeting?
Many new games are designed on the computers all the time; people of all ages ______ these games.
--- Who are the teenagers gathering at the school gate? --- Well, if you _____ know, they are all my visiting students.
Nothing taught by others can have the same effect on you as _____ learned by yourself.
In China, _______ bicycle is ______ popular means of transportation.
-- What do you think of the furniture on exhibition? --- Well, great! But I don’t think much of _______ you bought.