We already have ______ pencils, but we need two ______ pens.
After many attempts,she ________managed to get promotion.
There is no ________to what you can do if you try.
—Henry,________the light is ________when you leave the lab. —All right.
—________that middle school ________Beijing Normal University? —As far as I know,it is.
He opened the windows to ________ the smell of tobacco.