—Hurry up! The bus is coming.—Wait a minute. Don’t cross the street ____________the traffic lights are green.
My teacher encouraged me _______ more books.
The car is_______ expensive_______ I can’t afford it.
Our school life is ________________ happiness and sadness.
You are sure to fail the exam__________you study hard.
There ______a number of books in our school library. The number of books________getting larger than last year.