Questions 1 to 3 are based on the following conversation. At the end of the conversation, you will be given 15 seconds to answer the questions. Now, listen to the conversation. Which of the following is NOT true according to the conversation
A．Doctors will try plastic teeth on people. B．Doctors have made plastic teeth work on animals. C．Toothache always bothers people. D．Doctors are tying to transplant a person’s tooth to another person.