Questions 19 to 22 are based on the conversation you have Just heard.

A．Language elements.
B．Cultural differences.
C．Something happens when people from another culture want to communicate.
D．Practical problems in communications between different cultures.

A．To know whether they read the book or whether they understand the book.
B．As a common home assignment.
C．To help improve their writing.
D．To monitor their research.