Dialogue of Teaching Collection letter

Teacher : Hi, everybody. Today, we are going to talk about ¡§Collection Letters.¡¨ But first of all, do you remember what we learnt about ¡§formal business letter¡¨ last lesson?
Student : Yes. It includes ¡§Opening¡¨, ¡§Details¡¨, ¡§Action¡¨ and ¡§Closing¡¨.
Teacher : Very good. This time we are going to learn to write a formal letter with a purpose of collection.
Teacher : Collection is the noun of the word ¡§collect¡¨, can anybody tell me the meaning of the word ¡§collect¡¨?
Teacher : Student B: Collect means bring or gather together; get something from a number of persons or places.
Teacher : Good. In the commercial world, if you are a seller, what kind of things that make you need to write a letter to collect from the customer? Do you have any idea?
Student B : Money
Teacher : Good. The purpose of writing collection letters is to collect money or loan from customers or borrowers. ...