2 . During a decline in tourism, one national park in Thailand has witnessed a dramatic rise in “visitors” recently. So many are the hermit crabs（寄居蟹）flooding into the otherwise empty beaches of Koh Lanta that shells for them to live in have become in short supply.

The Thai government moved quickly to ease the housing shortage, launching a public appeal for empty shells that netted over 200kg. On December 5 these were distributed around the park in a ceremony.

Hermit crabs rely on shells to protect their soft bodies, moving to larger shells as they grow. On Koh Lanta and the surrounding smaller islands, their rapid increase seems to be a natural phenomenon, rather than directly related to the absence of tourists. But the shortage of shells maybe man-made: pretty ones have long been gathered to be sold as goods. Crabs had begun to make do with potential death-traps such as plastic caps and bottles.

The shell drive was part of a government initiative to “regain the balance of nature”. “I have instructed all national parks to do whatever it takes,” says Varawut Silpa-archa, the minister for natural resources. His inspiration comes from the pause in tourism brought on by COVID-19. A ban on international visitors and the closure of national parks have helped nature recover, bringing endangered leatherback turtles back onto Thai beaches. In the coastal provinces of Phang Nga and Phuket, turtles have laid the largest number of eggs for 20 years.

The government has decided to try to copy the short break forced on it by COVID-19 in future. From now on, all national parks will be required to close for a short period during the off season and to limit the number of tourists through a reservation system when they are open. Although such restrictions mean reduced earnings from tourism in the short term, in the longer run more parks may help to keep the tourists coming.

3 . What I Regret

At lunchtime, Jimmy, Patrick, Devon, and I began our regular routine of our lunches. I glanced across the busy cafeteria and saw the _________ student, Joel. He was holding his plate and waiting in lines.

Patrick _________ him too. “Why’s the new kid dressed like the headmaster?” he asked. Devon and Jimmy laughed.

“Joel’s cool. He’s in my English and history classes,” I said. However, I kept the _________ that Joel and I had become friends when we worked on a project together. We _________ that we were both enthusiastic readers — something I would never admit to Patrick, Jimmy, and Devon.

I saw that Joel was _________ toward us. “Don’t do it,” I thought, but in seconds he was at our table. My friends raised their eyebrows. Jimmy, Devon and Patrick piled their backpacks on the table and chairs so that there was no _________ left for another person to sit down. Patrick said, “I don’t think we have room.”

This _________ situation froze the air. I could _________ Joel looking at me, but I stared at my _________ as if it contained precious pearls of wisdom instead of rice and beans. After a long, uncomfortable pause, Joel ____________. I ____________ have spoken up for him, but I couldn’t walk away from my three friends, could I?

Joel didn’t speak to me after that ____________ He was soon ____________ around with another group of kids. A few months later, I saw an announcement about Joel being chosen to be president of the class book club. I was ____________ for Joel’s achievements, but I realized I had made a big mistake____________ I said nothing at the lunch table that day. Why was I so ____________ that my friends might find out that I like to read?

As I stared at the announcement, I knew I needed to ____________ to Joel even if he did not want to become my friend again. I was certain that my three friends would not ____________. I was also certain that I ____________ losing them as well. However, I knew that I would lose myself if I did nothing.

As the dismissal bell rang, I gathered up my books, took (a) deep ____________, and went to find Joel.

4 . It is fashionable today to criticize Big Business, and there is one issue on which the many critics agree: CEO pay. We hear that CEOs are paid too much (or too much relative to workers) , or that they control others’ pay, or that their pay is insufficiently related to positive outcomes. But the more likely truth is CEO pay is largely caused by intense competition.

It is true that CEO pay has gone up---top ones may make 300 times the pay of typical workers on average, and since the mid-1970s, CEO pay for large publicly traded American corporations has, by varying estimates, gone up by about 500%. The typical CEO of a top American corporation-from the 350 largest such companies-now makes about $18.9 million a year.

While individual cases of overpayment definitely exist, in general, the determinants of CEO pay are not so mysterious and not so trapped in corruption (腐败). In fact, overall CEO compensation for the top companies rises pretty much in line with the value of those companies on the stock market.

The best model for understanding the growth of CEO pay, though, is that of limited CEO talent in a world where business opportunities for the top firms are growing rapidly. The efforts of Americans highest-earning 1 % have been one of the more dynamic elements of the global economy.

It’s not popular to say, but one reason their pay has gone up so much is that CEOs really have upped their game relative to many other workers in the U. S. economy.

Today’s CEO, at least for major American firms, must have many more skills than simply being able to “run the company.” CEOs must have a good sense of financial markets and maybe even how the company should trade in them. They also need better public relations skills than their predecessors, as the costs of even a minor slipup can cause a bad consequence. Then there’s the fact that large American companies are much more globalized than ever before, with supply chains spread across a larger number of countries. To lead in that system requires knowledge that is fairly incredible.

There is yet another trend: virtually all major American companies are becoming tech companies, one way or another. An agribusiness company, for instance, may focus on R&D in highly IT- intensive areas such as genome sequencing (基因组序列). Similarly, it is hard to do a good job running the Walt Disney Company just by picking good movie scripts and courting stars ； you also need to build a firm capable of creating significant CGI (计算机生成图像) products for cartoon movies at the highest levels of technical sophistication and with many frontier innovations along the way.

On top of all of this, major CEOs still have to do the job they have always done- which includes motivating employees, serving as an internal role model, helping to define and extend a corporate culture, understanding the internal accounting, and presenting budgets and business plans to the board. Good CEOs are some of the world’s most powerful creators and have some of the very deepest skills of understanding.

5 . We’ve all been told to dress warmly or we’ll catch cold. But science says the common cold is caused by the virus, not the weather. Actually, according to researchers at Yale University, there just might be something to this old wives’ tale.

For decades, researchers have known that the virus replicates (复制) more readily in cooler environments, such as the nose, rather than at the warmer core body temperature. The reason for this, explains Ellen Foxman, an assistant professor at Yale University School of Medicine, long remained a mystery. Scientists didn’t know whether the virus itself worked better at colder temperatures, or the immune system worked worse. “No one could find anything,” she says.

Then Foxman and her colleagues studied what’s called the born immune system, which is present in every cell, and how it responds to various temperatures when the virus is present. In the lab, they examined airway cells from mice and found that the immune system produced fewer chemical substances called interferons at lower temperatures, allowing the cold virus to flourish.

In a study published this year, they found supporting results in human cells: At the warmer core body temperature, born immune systems that block viral growth are more active, and can stop and kill viruses. Now the team is trying to better understand the defenses the body uses to prevent the virus.

While wearing a scarf around your nose to warm it up might help prevent a cold, Foxman recommends washing your hands so you don’t pass the virus to your eyes, nose, or mouth in the first place. “If the virus isn’t in your nose, it can’t cause infection,” she says.

6 . As levels of carbon dioxide - CO₂ - in the atmosphere have been rising in recent decades, Earth has been warming. That’s because as a greenhouse gas, CO₂ traps heat in Earth’s atmosphere. That warming is one symptom of climate change. And it has the potential to affect food in many ways. Data now show that rising levels of CO₂ also can affect how nutritious a crop will be. Some of those data were reported last year in Annual Review of Public Health. Indeed, it noted that several studies have come to this conclusion.

Samuel Myers is an environmental health scientist at Harvard University in Cambridge, Mass. He was part of a team that has studied the potential effects of climate change on nutrition. In one 2014 study, his group looked at six major food crops: wheat, rice, field peas, soybeans, maize (corn) and sorghum. They exposed plants to different amounts of CO₂. Some got levels of between 363 and 386 parts per million (ppm), which were typical at that time. (CO₂ levels have since risen.) Other plants were exposed to more of that greenhouse gas as they grew — 546 to 586 ppm. Such levels are expected to develop within the next 50 years or so.

After harvesting the plants, the researchers measured their levels of vitamins, minerals and other nutrients. And plants grown with more CO₂ were less nutritious. Most people depend on cereal crops, such as wheat and rice, to meet their dietary needs for both zinc and iron. If crop levels of such nutrients fall, people may face an even greater risk of falling ill.

Scientists don’t yet know why CO₂ impacts levels of these nutrients. But the new findings suggest scientists may want to try breeding new varieties of crops that are less affected by CO₂. That way people will still get the most benefits from their greens and grains.