—Excuse me,but could I trouble you for some change?—________.Will pennies do?
In any case, parents should make clear _______, if any thing, the children are expected to pay for with the money.
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.