---Look at the boy running on the playground. Is it David? ---It ______ be him. I saw him go to the teachers’ office just now.
He made his final __________ last winter and__________ from then on.
Do you know what__________ before you __________?
The price of the book is __________ so I would rather not buy it.
My hobby is collecting stamps.I need __________ before I have 3000 stamps.
The number of the classes in our school is __________ than__________ of any other school in Nanjing.