—Listen ! Helen is singing in the next room.It ____ be Helen. She has gone to Beijing.
The workers will build a new railroad______ the two cities.
Where is Class________ ? It’s on the ______ floor.
What do you usually have for________ breakfast? A piece of bread and ______ egg.
—Can you tell me ____ the prize, Tom? —Last year。
Today, computers are really helpful. They ____ everywhere.