1 . Why It’s Hard to Lose Weight

What makes people gain weight? This seems like a simple enough question to answer. If we eat a lot and don’t do enough exercise, we will become fat.     1    

As we know, what we eat greatly affects our weight. It is widely accepted that people have 100% control over what they eat and how much they eat. This, however, is partly true.     2     You may rarely touch vegetables while overeating fried chicken. Meanwhile, the serving size and the background music can both affect how much we eat.

Our bodies themselves can decide whether we are more likely to gain weight or lose weight. Scientists have found that the more delicious the food, the more excited our brains get.     3     Compared to people of normal weight, fat people feel more excited when they see delicious   food.

Also, our bodies use a variety of hormones (激素) to tell our brains whether they are hungry or full.   Ghrelin(胃饥饿素), for example, tells the brain that the body wants food. Leptin(瘦蛋白), meanwhile, tells the brain that it’s time to stop eating. Ghrelin and leptin help us to maintain a healthy weight.     4     As we get fatter, the levels of leptin in our bodies rises.   Our brains are told not to eat all the time. In the end, they would no longer trust leptin and would stop responding to its “warnings”. When we start to lose weight, leptin levels drop. Our brains think we are hungry and makes us find food in our fridge.

    5     They may have tried very hard, but their bodies are working against their will.

4 . It was a quiet early afternoon in the library, and we librarians were enjoying a chat at the library desk. Suddenly, a regular reader, who had been reading a magazine, marched up to us, gave us an annoyed “Shush (嘘)!” and went back to her seat.

Shocked into silence, we tried not to laugh. How strange for a group of librarians to be shushed by a reader! Shouldn’t it be the other way around?

Well, it seems hard to explain. If you’re a baby boomer (婴儿潮出生的人) like me, you probably remember libraries as places of adults’ silent reading. These days, however, libraries are more like busy community centers, where being noisy to some degree is the new normal, especially when kids are taking part.

I am a loud librarian. My voice is naturally on the louder side. The hundreds of programs I led as a children’s librarian were filled with singing, dancing, movement exercises and cheerful readings of books with crowds of children and their caregivers. No shushing allowed!

Growing knowledge about the importance of kids and teens learning through hands-on experiences has since caused a sea change in how public libraries connect with young readers. These types of programs like board games, poetry reading and story times certainly aren’t designed to be silent.

But it’s a balancing act. Not all readers—or librarians—like the idea of a noisy library. It’s clear to me now that on the day my colleagues and I were shushed by a reader, we should have been using our “library voices” as we talked. Still, it’s unlikely that libraries will ever return to the days when they were places of silence. There’s just too much fun and learning happening. I heartily agree with my friend Rachel Payne, an early-childhood service educator at the Brooklyn Public Library, who told me, “When I visit a library and it is quiet, I always feel a bit sad. A library where conversations are happening and tables are full is a very good thing!”

5 . Age is truly just a number if our hearts are young. Lee Minor, an 85-year-old retired psychologist, has________this by finishing his 600th marathon race with 32 members of his family by his side. “Runners don’t have a________line. We just keep going,” he toldGood Morning America. “I felt________running with my family.” Minor has been running three days a week since 1969, and his heart is filled with enthusiasm for running.

“I like to run in all kinds of________. It is so childish as the rain touches your face. And I love to come here after snow and you watch your________as you go along.” he concluded.

Minor’s enthusiasm for running is________. “It is my joy. And I want to live as long as I can. And I mean live, not________.” His words ring true for Ron Robert, a man diagnosed with Alzheimer’s disease who decided to ________ a three-year bachelor of artsprogram at King’s University College in London, Ontario. “I was always taught early in life that the brain is like the most ________instrument we have in our body,” said Robert.

Last fall, Robert graduated from the university, despite the challenges of his illness. “When I went across the stage, and as I’m getting my________, the kids all stood up andyelled and clapped,” he________. “I had to hold back the tears. It was something else, just wonderful.” He hopes that his story will give hope to others facing________difficulties. “There will come a time when I won’t be able to, and I fully________that. Butin the meantime, I’m living a full life.”

The stories of Minor and Robert are reminders that age and illness need not________us. We can choose to pursue our________and live life to the fullest, no matter whatchallenges we may face.

When I was young, I lived in a quiet small town with my mom. My mom was beautiful and kind but one day she got a contagious(传染的) disease, which was said to be very serious. I was worried about her , seeing her becoming thinner and paler day by day. Mother’s Day was coming. I decided to buy mom some flowers to make her happy. There was only one flower shop in the town-Mr. Rocco’s.

It was time for Mr. Rocco to shut up shop when I hurried into the florist’s (花店). “Now, what is it that you want?” Mr. Rocco turned to me. “I want the most beautiful flower you have.” I replied, still breathing hard. “And just how much do you have to pay for this most beautiful flower?” I held out a wet hand showing a quarter and a dime. He nodded, thought for a while and then showed me a plant on the counter. “I can give you this one for 35 cents.” he said. “Aw, no,” I protested, looking desperately at the poor plant “it looks like a weed (野草)!” About 18 inches high, the plant was in a small pot covered with faded red paper. “Now trust me, boy — I promise that tomorrow morning when you get up, you will find your most beautiful flower.” said Mr. Rocco. I knew him to be a good honest man, so I agreed to take it. I believed what Mr. Rocco said about the flower and hoped tomorrow morning there would be a nice surprise for my mom.

It was almost midnight when I arrived home. Mom was seriously sick and using the front bedroom. I looked in to see if she was asleep, and then quietly tiptoed in and set the plant on the table beside her bed. I wanted her to be surprised when she woke on Mother’s Day.

The next morning, I dressed and hurried downstairs.

My dear Mom died the next night.

9 . Machine learning sees reasoning as a categorization task with a fixed set of predetermined labels. It views the world as a fixed space of possibilities, calculating and weighing them all. This approach, of course, has achieved notable successes when applied to stable and well-defined situations such as chess or computer games. When such conditions are absent, however, machines struggle.

In 2008, Google launched Flu Trends, a web service that aimed to predict flu-related doctor visits using big data. The project, however, failed to predict the 2009 HINI flu outbreak. After several unsuccessful adjustments to its algorithm (算法), Google finally stopped the project in2015.

In such unstable situations, the human brain behaves differently. Sometimes, it simply forgets. Instead of getting trapped in irrelevant data, it relies only on the most recent information and makes creative decisions. This is a feature called intelligent forgetting. Adopting this approach, an algorithm that relies on a single data point would have reduced Google Flu Trends' prediction error by half.

Intelligent forgetting is just one dimension of psychological AI, an approach to machine intelligence that also includes other features of human intelligence such as causal reasoning, intuitive (直觉) psychology, and physics. Soon, this approach to Al will finally be recognized as fundamental for solving poorly-defined problems. Exploring these amazing features of the human brain will finally allow us to make machine learning smart.

One feature of psychological Al is that it is explainable. Until recently, researchers assumed that the more transparent an AI system was, the less accurate its predictions were. This mirrored the widespread but incorrect belief that complex problems always need complex solutions. Now, this idea will be laid to rest. As the case of flu predictions illustrates, powerful and simple psychological algorithms can often give more accurate predictions than complex algorithms. Psychological AI opens up a new vision for explainable AI: Instead of trying to explain complex systems, we can check first if psychological Al offers a simple and equally accurate solution.

Without the help of human psychology, it will become clearer that the application of this type of machine learning to unstable situations eventually runs up against impassable limitations. We will finally recognize that more computing power makes machines faster. Not smarter.

10 . Most of us have told a lie at one time or another. Some lies are harmful. Others are mostly harmless. Still other lies may even be created with the best of intentions. But no matter what kind of lie you tell, it takes a great deal of brainpower to keep your lie covered.

People lie for different reasons. Sometimes they do it to make themselves look better. Sometimes they lie to get out of trouble. Some lies are well-intended, which scientists call “prosocial lies”. Maybe you tell your parents that you loved the sweater they gave you for your birthday (even though you were really hoping for a new cell phone). That’s a prosocial lie.

When you tell the truth, your brain doesn’t have to do anything unusual. Lying takes much more work. For example, when you are late for class, you tell a lie that you have to stop by the library and pick up a book. Your teacher may ask to see the book or even ask you to read it. This may result in a series (系列) of lies, causing a lot of brain work done in the prefrontal cortex (前额皮层). It’s the part in charge of working memory. Working memory keeps something in mind just for a little while. When you use self-control to keep from telling the truth, this part comes into play.

Spending so much brainpower trying to keep a story straight means prefrontal cortex has a harder time doing other tasks that require planning, self-control or working memory, such as planning a study schedule. Kid’s prefrontal cortex is not fully developed until around age 25. So they have fewer resources (资源) there to begin with. That is why researchers feel it’s important that kid students find dependable people to whom they can safely tell even painful truths about themselves.

“Nearly all cultures value honesty,” Talwar says. And, she adds, “There are things people can do to help create a culture that strengthens the value of honesty. Rather than punishing people for lying, it is more important to praise them for telling the truth.”