--How many girls are there in your class ?-- _______ them _______ over twenty.
It’s widely known that you won’t achieve success _____ you work hard.
He thinks himself somebody, but we think him _____.
The boy failed the exam because he _____ a lot of time playing the computer games.
The shy girl prefers _____ in the KTV to _____ on the stage.
You can improve your English _____ practicing more.