Question 18 is based on the recording you have just heard.

Recording One

听力原文

    Today I’m going to talk about a very special kind of person. Psychologists call them “masters of deception”: those rare individuals with a natural ability to tell with complete confidence, when someone is telling a lie. (16) For decades, researchers and law enforcement agencies have tried to build a machine that will do the same thing. Now, a company in Massachusetts says that by using magnetic brain scans, they can determine with 97% accuracy whether someone is telling the truth. They hope that the technology will be cleared for use in American courts by early next year.

    But is this really the ultimate tool for you, the lawyers of tomorrow? (17) You will not find many brain scientists celebrating this breakthrough. The company might be very optimistic, but the ability of their machine to detect deception has not provided credible proof. That’s because the technology has not been properly tested in real world situations. In life, there are different kinds of lies and diverse contexts in which they’re told. These differences may elicit different brain responses. Does their hypothesis behind the test apply in every case? We don’t know the answer, because studies done on how reliable this machine is have not yet been duplicated. 

    Much more research is badly needed. Whether the technology is eventually deemed reliable enough for the courts will ultimately be decided by the judges. Let’s hope they’re wise enough not to be fooled by a machine that claims to determine truthfulness at the flip of a switch. They should also be skeptical of the growing tendency to try to reduce all human traits and actions to the level of brain activity. Often they do not nap that easily. Moreover, understanding the brain is not the same as understanding the mind: some researchers have suggested that thoughts cannot properly be seen as purely “internal”.

    Instead, thoughts make sense only in reference to the individuals’ external world. So while there may be insights to be gained from matching behavior to brain activity, those insights will not necessarily lead to justice in a court of law. Problems surround the use of machines to spot deception, at least until it has been rigorously tested. (18) A high-tech test that can tell when a person is not telling the truth sounds too good to be true. And when something sounds too good to be true, it usually is.

18. What does the speaker think of using a high-tech test to determine whether a person is telling the truth? 

解析：A。录音最后说，通过高科技测试来告诉别人一个人是否在说谎这件事听起来就显得太美好而不太真实。而当一件事听起来好得令人难以置信时，它通常就是不真实的。也就是说，讲话者倾向于认为用机器测谎本身就是不真实的，not true与not to be trusted表意相同，因此A项正确。