—I wonder how much you charge(要价) for your services.—The first two are free the third costs¥30.
Use your head, _______you’ll work out the problem.
_______ is known to all, Lu Xun was famous as a great thinker.
I would appreciateback this afternoon.
If something ________, it becomes less and less and eventually disappears completely.
It’s the first time ______ he has helped us.