— Who would you like to see you off at the airport?—           . Just say “good-bye” at home.

—There is still a copy of the book in the library. Will you go and borrow         ? —No, I’d rather buy         in the bookstore. 

     may have a chance to be successful if he doesn’t try his best.

I knocked on the door but ______ answered.

 In the west, people make _______ a rule to send Christmas present to their relatives and friends.