A、They come into his laboratory lack of confidence. B、They come into his laboratory full of confidence. C、They have been in the

W: Today we have Daniel Leviton with us to share his opinion on confidence. Daniel is an author, neuroscientist, doctor, and teacher. Welcome!
M: Thank you. Today, I would like to tell you that having confidence will help you a lot, but being over-confident will lead you to something bad. Like this Mark Twain quote: “It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just isn’t so.”
W: What does that mean?
M: I will give you an example in the medical field. If you’re sure that an alternative treatment will help cure you better than Western medicine, you will abandon the traditional treatment. Two thirds of cancer patients think that alternative medicine will prolong their lives.
W: Then what is the result of this?
M: In fact, patients who turn to an alternative treatment are twice as likely to die of their cancers, and they die earlier.
W: That is because if you’re sure that your choice of something is right, you’re not gonna be open-minded about any new evidence that might come in that could or should cause you to change your mind. Am I right?
M: You are totally right. In addition to being a doctor, I’m a college professor as well, and I train PhD students for careers as neuroscientists. They come into my laboratory full of confidence. They have been at the top of every class in their entire lives. I spend most of my time trying to teach them that they don’t know everything they think they do. My job as a teacher really is to unteach them.
W: But how can you unteach students when your job is to teach them?
M: I’m always asking, why do you think that? What’s the evidence? Knowledge can only be created in an environment where we’re open to the possibility that we’re wrong. I think that all of us should be capable of this kind of critical thinking.
W: A great lesson for all of us.
Questions 5 to 8 are based on the conversation you have just heard.
5. What are the speakers mainly talking about?
6. What does the man say about patients who turn to an alternative treatment?
7. What does the man say about his students?
8. What can we learn from the end of the conversation?