题目

人脑内有一种“沉默突触”，它具有突触结构，但没有信息传递的功能。你推测最可能的原因是（ ）A. 突触小体中没有细胞核B. 突触后膜缺乏相应的受体C. 突触间隙不存在水解神经递质的酶D. 突触小体能够释放相应的神经递质 答案：【答案】B【解析】突触前膜释放神经递质作用于突触后膜上的受体，使得下一个神经元兴奋或者抑制，“沉默突触”只有突触结构，没有信息传递功能，由此推断，没有信息传递功能可能是由于突触小泡不能合成神经递质，或者突触后膜缺乏相应受体从而导致突触没有信息传递功能。突触包括突触前膜People often view the “last” moments of an event positively simply because they signal the end of an experience, say experts. University of Michigan researchers found that even if an experience is painful or negative, but ends on a good note, people will consider it to be positive.“Endings are powerful,” said Ed O’Brien, a graduate student in the Department of Psychology at the University of Michigan.O’Brien and colleague Phoebe Ellsworth, the Frank Murphy Distinguished Professor of Law and Psychology, conducted a chocolate tasting experiment with 52 college students to test the theory.Volunteers could taste five different Hershey’s Kisses chocolates—milk, dark, cream, caramel and almond – but did not know in advance how many pieces they would eat or the type. Participants rated how much they enjoyed the chocolate and described each flavor so that the researchers could record the order in which the randomly (随机的) selected treats were eaten. Volunteers were assigned to the “next” or the “last ” condition by chance. In the “next” condition, the experimenter said “Here is your next chocolate” before offering each chocolate, including the fifth. For the “last” condition, the experimenter said “Here is your last chocolate” before offering  the fifth chocolate. These participants rated the fifth chocolate more enjoyable than volunteers in the “next” condition. As predicted, participants who knew they were eating the final chocolate of a taste test enjoyed it more. In fact, when asked to pick their favorite chocolate, the majority of “last” participants chose the fifth – even though the flavor of the fifth was randomly chosen. They also rated the overall experience as more enjoyable than volunteers who thought they were just eating one more chocolate in a series. O’Brien says these findings may have far-reaching implications. For example, the last book or film in a series or the last speaker in a symposium (研讨会) may receive unwarranted praise. The last job applicant, meanwhile, may look more qualified.小题1:Which of the following is TRUE about the experiment?A．The majority of “last” participants chose the almond flavor as their favorite.B．Some participants enjoyed the experiment more because the last flavor tasted better. C．The result would be different if researchers had used another brand of chocolate.D．Some participants didn’t know it was their last chocolate when offered the fifth one.小题2:What does the underlined word “unwarranted” in the second-to-last paragraph mean?A．Fake. B．Unwanted. C．Unreasonable. D．Insincere.小题3:Which of the following is the best title for the article?A．“Last” is the best.B．Why “last” matters most.C．It is the last step that is the hardest.D．He who laughs last laughs best.