A : "Hello, C and D!"

C : "Hey, A and B!"

D : "What are you doing here?"

B : "We're looking for a book to read. Would you like us to pick an interesting one?"

C : "Sure. We have some books that might interest you."

D : "The interesting books are on the highest bookshelf."

C : "A, would you please bring me the leader?"

A : "Sure!"

C : "Thanks. Here you go."

B : "I choose this one. How about you?"

A : "So do I. Let's go back to the class."

B : "Alright. Thanks C, D!"

C : "No problem."