—What’s on the floor?— A. That’s my key. B. There’s a book. C. It’s red. D Yes , it is .
The cleaners make a great contribution to _____ the city clean.
He is a writer _____ a singer.
She was heard _____ an English song in her home last night.
Not only his parents but also his brother _____ to the Summer Palace. They haven’t been back.
Tell me everything _____ you know.