— ____ you _______your book to the library? — Yes. I returned it yesterday. A. Did, return B. Have, returned C. Will, return
—_______ do you talk to your teacher at the School Air?—Once a week.
A library with two hundred thousand books _______ to the school last year.
The customs in America are different _______ those in China.
We visited Beijing University _______ the first day of our trip.
_______ is necessary for us _______ our own dreams.