What might be the best title for the passage?

(单选题)21. （ ） (单选题)20. （ ） (单选题)19. （ ） (单选题)18.（ ） (单选题)17. （ ） (单选题)16.（ ） (单选题)—______ are these apples?—$ 3.99. (单选题)In front of the whole class, he made his promise ______ he w (单选题)We don’t understand the passage ______ there are a few new w (单选题)The desk is light. I can carry it ______.