(1) The professor glanced hastily around the room as he entered, then he looked suspiciously over at the blackboard. While removing his overcoat he read the scrawl that the previous class had left, and judging it unnecessary clutter, he daintily lifted the eraser and waved it back and forth in front of the class, until the board was clear. He checked his watch. It wasn't yet time to start class, so the teacher started to pace back and forth, nervously stroking the lock of hair that covered his bald spot. This man had obviously been sitting in a stuffy office in front of a computer screen for too long. Math professors should get out in the sun more. I noticed his pale skin and the many nicks he’d gotten shaving his overly-sensitive face.
(2) Finally it was time to start. He began by presenting an example: you want to house a football team with 20 white players and 20 black players. What is the probability that all of the pairs of roommates will be of the same color? “A hundred percent”, I said. Okay. I know it was a poor attempt at humor, but I could have sworn no one had heard me. Not one person flinched, sighed, moaned, or giggled. Nothing. They didn’t even turn their heads to see what jerk said that.
(3) “Okay, either everybody in this class is dead, or I am” I thought. I pinched myself. No, it wasn’t me. I watched everyone else copy down what the teacher had written on the board. So they were at least animate. The professor was doing a good job of dealing with the dilemma and posed questions at which a few members of the group guessed. I wondered why he was being paid to talk to corpses.
(4) Yes, something was definitely wrong here. This man was talking to 30 dead people who were diligently copying down his every word. Now the only reason I could see for the lack of response, by his audience was that they didn't share my interest in probability. That seemed reasonable but I couldn’t imagine why anyone would take a 400-level math course unless he was a math major, or at least a math minor. No, these people were interested in the topic.
(5) Maybe they all understood exactly what he was saying and didn't have to ask any questions. I still couldn’t explain the blank stares and the silence, as heavy as the silence of parting lovers, whenever the professor asked a question. The room was too big for the quiet and I felt awkward there. Everyone seemed to want to leave, but there he was, the man up there with the chalk holding the whole class silent and holding all of us hostage.
(6) All of these tortured faces were looking straight ahead and they were taking it all down, just like it was, so that they could go back to their little cells and look at it over and over again until they had it memorized. And if they couldn't understand it, they would ask someone else in the class who would invariably say, “I don’t know. I’m not sure I understand that part either.”
(7) Nobody ever goes to a teacher’s office hours, either. I’ve gone to see my teachers, and there’s never anyone else there. The professor sets up time when he can sit and wait for students to talk to him and no one shows up, week after week. It’s nice because teachers are human, too, and they need time alone. I guess that zombies don’t leave their cells unless they have class. I looked over at the people next to me. How did they get that way in the first place?
(8) What in the world was I doing in this ridiculous class, writing down a description of the teacher’s clothing? I was listening to the words, and I even had some vague comprehension of what he was discussing, but I really couldn’t explain my attendance. But what I really couldn’t explain was the professor’s presence. He seemed to have a good sense of humor about the fact that we were all sitting there dead, but I don’t know how he could face us that way. I kept wanting to get up and shout at the class myself, say, “Hey, what are you doing here? Aren’t you paying for this? Didn’t you come here to learn? I couldn’t face these zombies as boldly as this man was. He didn’t scream or despair. He just kept on talking. And I kept on thinking: This is an institution of higher learning.” 

In this section，there are ten incomplete statements or questions，followed by four choices marked A，B，C and D．Choose the best answer.

 (1) It's easy to keep your aging brain as nimble as it was in college. Log on to a website full of brain games or download the right apps, and within 20 minutes you'll be doing your part to sharpen your memory and slow the inexorable decline of your mental functions. At least that's what the companies behind this booming industry would have you believe. But is it true?
(2) Concrete proof about the benefits of brain games is hard to come by, experts say, when it comes to measurably improving aspects of mental fitness, like having a good memory or sound reasoning. "People would really love to believe you could do something like this and make your brain better, make your mind better, "says Randall W. Engle, a primary investigator at the Attention and Working Memory Lab at the Georgia Institute of Technology "There’s just no solid evidence.”
(3)That's not to say brain games are without benefit. Experts say these kinds of mental exercises can change your brain-just not in a way that necessarily slows its aging. The brain changes with just about everything you do, including mental training exercises. But numerous studies have shown that brain games lack what researchers call "transfer" In other words, repeating a game over and over again teaches you how to play the game and get better at it but not necessarily much else.
(4)"It's like, you walk through fresh snow, you leave a trace. If you walk the same route again, the trace gets deeper and deeper," says Ursula Staudinger, director of the Butler Columbia Aging Center at Columbia University. "The fact that structural changes occur [in the brain] does not imply that in general this brain has become more capable. It has become more capable of doing exactly the tasks it was practicing." 
(5)Brain-game designers, not surprisingly, disagree. Michael Scanlon, chief scientific officer at Lumosity, a large brain-game company, refers to a 2007 study he led as support for his company's getting into the brain-game business in the first place. "Our basic intention was to release a product that helps people improve cognitive abilities," he says. Scanlon says the research, which Lumosity funded and conducted, found that online-based brain training can improve thinking. The small study of 23 people is one of several studies Lumosity has performed, though most have not been peer-reviewed.
(6)As the brain-game industry has grown-revenue topped $I billion in 2012 and is projected to hit $6 billion by 2020, according to a report from neuroscience market-research firm Sharp Brains--so has the criticism. More than 70 prominent brain scientists and psychologists signed a withering statement on the subject last year. The open letter, organized by the Stanford Center on Longevity and covered by media outlets across the world argued that claims on behalf of brain games about improved cognition were "frequently exaggerated and at times misleading." The scientists also laid out criteria that the games would have to meet to convince them of their merit. It's a tough list.
(7)Still, Staudinger allows that brain games do have the benefit of being fun-which may make them a worthwhile way for people of any age to spend time. There's no question that many consumers have become devoted to them. Lumosity, which offers some games free and a premium membership at a cost, says it reached 50 million members in 2013.
(8)The issue most scientists have with people playing the games frequently is the opportunity cost: you could be doing something else that actually would improve your cognitive ability. Most researchers agree that the activity most clearly proven to slow aging in the brain is aerobic exercise. Other factors that sound scientific research has shown to help an aging brain include healthy dietary choices, regular meditation and learning new things.
(9)As brain games evolve and new, impartial research conducted, it's possible that the scientific consensus about their impact on the brain will change. But Engle doesn't think it's likely. "I need fairly substantial evidence that it's not kind of a gimmick," he says. "I'm a scientist.” 

阅读文章，回答下列问题。

(1) Freedom’s challenge in the Atomic Age is a sobering topic. We are facing today a strange new world and we are all wondering what we are going to do with it. What are we going to do with one of our most precious possessions, freedom? The world we know, our Western world, began with something as new as the conquest of space.
(2) Some 2,500 years ago Greece discovered freedom. Before that there was no freedom. There were great civilizations, splendid empires, but no freedom anywhere. Egypt, Babylon, Nineveh, were all tyrannies, one immensely powerful man ruling over helpless masses. In Greece, in Athens, a little city in a little country, there were no helpless masses, and a time came when the Athenians were led by a great man who did not want to be powerful. Absolute obedience to the ruler was what the leaders of the empires insisted on. Athens said no, there must never be absolute obedience to a man except in war. There must be willing obedience to what is good for all. Pericles, the great Athenian statesman, said: “We are a free government, but we obey the laws, more especially those which protect the oppressed, and the unwritten laws which, if broken, bring shame.”
(3) Athenians willingly obeyed the written laws which they themselves passed, and the unwritten, which must be obeyed if free men live together. They must show each other kindness and pity and the many qualities without which life would be intolerable except to a hermit in the desert. The Athenians never thought that a man was free if he could do what he wanted. A man was free if he was self-controlled. To make yourself obey what you approved was freedom. They were saved from looking at their lives as their own private affair. Each one felt responsible for the welfare of Athens, not because it was imposed on him from the outside, but because the city was his pride and his safety. The creed of the first free government in the world was liberty for all men who could control themselves and would take responsibility for the state. This was the conception that underlay the lofty reach of Greek genius.
(4) But discovering freedom is not like discovering atomic bombs. It cannot be discovered once for all. If people do not prize it, and work for it, it will depart. Eternal vigilance is its price. Athens changed. It was a change that took place unnoticed though it was of the utmost importance, a spiritual change which penetrated the whole state. It had been the Athenians’ pride and joy to give to their city. That they could get material benefits from her never entered their minds. There had to be a complete change of attitude before they could look at the city as an employer who paid her citizens for doing her work. Now instead of men giving to their state, the state was to give to them. What the people wanted was a government which would provide a comfortable life for them; and with this as the foremost object, ideas of freedom and self-reliance and responsibility were obscured to the point of disappearing. Athens was more and more looked on as a cooperative business possessed of great wealth in which all citizens had a right to share.
(5) She reached the point when the freedom she really wanted was freedom from responsibility. There could be only one result. If men insisted on being free from the burden of self-dependence and responsibility for the common good, they would cease to be free. Responsibility is the price every man must pay for freedom. It is to be had on no other terms. Athens, the Athens of Ancient Greece, refused responsibility, she reached the end of freedom and was never to have it again.
(6) But, “the excellent becomes the permanent,” Aristotle said. Athens lost freedom forever, but freedom was not lost forever for the world. A great American statesman, James Madison, in or near the year 1776 A.D. referred to “the capacity of mankind for self-government”. No doubt he had not an idea that he was speaking Greek. Athens was not in the farthest background of his mind, but once a great and good idea has dawned upon man, it is never completely lost. The Atomic Age cannot destroy it. Somehow in this or that man’s thought such an idea lives though unconsidered by the world of action. One can never be sure that it is not on the point of breaking out into action, only sure that it will do so sometime.