You're rushing to work and a man ahead of you falls down on the sidewalk. Do you stop to help? In a study of by-standers, it was found that some people keep on walking.

    "There is a tendency to decide that no action is needed," says a psychologist, "In order to take action, you have to work against them." Here are some common thoughts that stop you from helping.

    ●Why should I be the one? I'm probably not the most able person in this crowd. You might think someone older or with more medical knowledge should offer assistance.

    ●What if he doesn't really need my help? The fear of embarrassment is powerful; no one wants to risk looking foolish in front of others.

    ●No one else looks concerned. We can follow the people around us, but most people tend to hold back their emotions in public.

    "If you spot trouble and find yourself explaining inaction, force yourself to stop and evaluate the situation instead of walking on," says the psychologist. "Then retry to involve other people; you don't have to take on the entire responsibility of being helpful. Sometimes it's just a matter of turning to the person next to you and saying, 'It looks like we should do something.' Or asking someone if an ambulance has been called and, if not, to call for one. Once you take action, most people will follow you."

    Unlike most other holidays, the history of April Fools' Day. Sometimes called All Fools' Day, is not as the totally clear. The only point in time that can be agreed on as the beginning of this tradition was 1582,in France. Before that year, the New Year was celebrated for eight days, beginning  on March 25.The reform of the calendar celetxration reached the highest point on April l_With the riform of the calendar under Charles 1X,the Gregorian calendar (公历, 阳历）was introduced, and New Year's Day was moved to January 1.

    However, because in those days communications were not as developed as they are today, many people did not receive the news for several years. Some people refused to accept the new calendar and continued to celebrate the New Year on April, These backward people were considered “foots” by other peopk. They were often sent on “fools” errands (徒劳无益的工作)or were made the taragets of jokes.

    This developed, over time, into a tradition of playing a trick on someone on the first day of April. The tradition eventully spread to England and Scotland in the eightreenth century. It was later introduced to the American colonies of both the Britain and Francc.April Fools' Day thus developed into an  international fun feast,so to speak,with different nationalities specializing in their own kind of humor at the expense of their friends and families.

    ARNOLD Schwarzenegger is back, once again taking on his iconic killer robot role, the T-800, in August's new movie Terminator Genisys. While the T-800 model—even if it can be evil—has a fond place in moviegoers' hearts, the reality of autonomous machines is no joke, according to scientists.

    Autonomous weapons use artificial intelligence (AI) to choose targets without human help. They were described as “the third revolution in warfare, after gunpowder and nuclear arms” in an open letter signed by over 1,000 important technology figures in July. The list included British scientist Stephen Hawking and Apple co-founder Steve Wozniak. They asked governments around the world to ban autonomous weapons, warning that killer robots could start ethnic cleansings and an arms race.

     “They will look like tanks. They will look like battleships. They will look like jet fighters,” UK robotics professor Noel Sharkey told CNET, a leading technology website.

    But unlike these machines, which require a human hand in their action, so-called “killer robots” would have some decision-making abilities and the ability to act on their own.

     “If any major military power pushes ahead with AI weapon development, a global arms race is almost inevitable,” said the letter released at the 2015 International Joint Conference on Artificial Intelligence in Buenos Aires, Argentina.

    The idea of an automated killing machine was made famous by Schwarzenegger's first Terminator movie in 1984. While no red-eyed robots have been sent after human beings, the idea of AI being used as a weapon has gotten much more likely in the years ever since. The US military is already developing autonomous flying vehicles that can carry out all the steps of a strike mission without a human controlling them, according to a May report in Nature magazine.

    Scientists have even painted a destructive picture of autonomous weapons falling into the hands of terrorists or warlords hoping to carry out ethnic cleansings.

     “The development of full artificial intelligence could lead to the end of the human race,” Hawking said to the BBC in 2016.

Authorities are gradually waking up to the risk of robot wars. Last May, for the first time, the United Nations brought governments together to begin talks on autonomous weapons systems.

    Still, a ban on autonomous weapons is “easier said than done”, commented The Guardian. The dual (双重的) uses of the AI technology—for harm and for good—is difficult to manage. This is because the exact same technology can be used in a wide range of ways, the paper said.

Five years ago, when I taught art at a school in Seattle, I used Tinkertoys as a test at the beginning of a term to find out something about my students. I put a small set of Tinkertoys in front of each student, and said: "Make something out of the Tinkertoys. You have 45 minutes today - and 45minutes each day for the rest of the week."

    A few students hesitated to start. They waited to see the rest of the class would do. Several others checked the instructions and made something according to one of the model plans provided. Another group built something out of their own imaginations.

    Once I had a boy who worked experimentally with Tinkertoys in his free time. His constructions filled a shelf in the art classroom and a good part of his bedroom at home. I was delighted at the presence of such a student. Here was an exceptionally creative mind at work. His presence meant that I had an unexpected teaching assistant in class whose creativity would infect(感染) other students.

Encouraging this kind of thinking has a downside. I ran the risk of losing those students who had a different style of thinking. Without fail one would declare, "But I'm just not creative."

"Do you dream at night when you're asleep?"

"Oh, sure."

"So tell me one of your most interesting dreams." The student would tell something wildly imaginative. Flying in the sky or in a time machine or growing three heads. "That's pretty creative. Who does that for you?"

"Nobody. I do it."

"Really-at night, when you're asleep?"

"Sure."

"Try doing it in the daytime, in class, okay?"

    One October morning, I got off the all-night train in Mandalay, a city in Myanmar. A rough man came up and offered to show me around. The price he asked was less than I would pay for a bar of chocolate at home. So I climbed into his trishaw(三轮车).

    As he was showing me around, he told me how he had come to the city from his village. He'd earned a degree in mathematics. His dream was to be a teacher. But of course, life is hard here, and so for now, this was the only way he could make a living. Many nights, he told me, he actually slept in his trishaw so he could catch the first visitors off the all-night train.

And very soon, we found that in certain ways, we had so much in common—we were both in our 20s, we were both fascinated by foreign cultures—-that he invited me home.

    So we turned off the wide, crowded streets, and came to rough, wild alleyways(小巷). I really lost my sense of where I was, and realized that I could easily get cheated or something even worse.

    Finally, he stopped and led me into a hut. And then he reached under his bed. Something in me froze. I waited to see what he would pull out. And finally he took out a box. Inside it was every single letter he had ever received from visitors from abroad.

    So when we said goodbye that night, I realized he had also shown me the secret point of travel, which is to go inwardly(向内心)as well as outwardly to places you would never go otherwise, to go into uncertainty, even fear.

    At home, its dangerously easy to think we're on top of things. Out in the world, you are reminded every moment that you're not, and you can't get to the bottom of things, either.

We've all heard the advice to "get out of your comfort zone" by taking on a new challenge. A recent study goes a step further: Make discomfort a direct goal. That's more likely to motivate you {#blank#}1{#/blank#} if you only focus on what you hope to learn.

In the first of five experiments, the researchers assigned several hundred students training at Second City Chicago {#blank#}2{#/blank#}（participate） in a small-group improvisation（即兴） exercise, and then instructed half of the group that their goal during the session was "to feel awkward and uncomfortable." The rest, {#blank#}3{#/blank#}（that） in the control group, {#blank#}4{#/blank#}（tell） to "feel yourself developing new skills." Members of the first group kept at the exercise longer than the others did and took {#blank#}5{#/blank#}（great） risks.

Experiments {#blank#}6{#/blank#}（involve） other dimensions of personal growth—engaging in expressive writing, learning about gun violence, and hearing about opposing political {#blank#}7{#/blank#}（belief）—produced similar results.

Reframing anxiety as excitement has been proven a way to improve singing in front of strangers, and thinking of stress as {#blank#}8{#/blank#} means to boost achievement demonstrated a stress-management technique.

"When people reinterpret negative experiences as {#blank#}9{#/blank#}（function）, they are more willing to engage in tasks that call forth those experiences," the researchers explain. "Instead of seeing discomfort as unrelated to the goal {#blank#}10{#/blank#} a signal to stop, they will start perceiving it as a sign of progress toward their goal."