---Do you know_______ the books on the shelves? --- Sorry, I can’t count them, because there are _______books.A. a number of; the number ofB. a number of; a numberC. the number of; a number of
— Would you mind turning up the music? — ________. Dad is sleeping now.
The cars _________ yesterday sell very well.
My parents usually take a walk ______ dinner to keep healthy.
Today is Tom’s______birthday.
He stepped into the office, _____down and began to fill in the forms.