Xuan paper, known as one of the Four Treasures of Study, first came into     1     (exist) in Xuan Prefecture in the Tang Dynasty. The traditional skill of making the paper     2     hand has been passed down through generations. The process takes as many as 108 steps, all of     3     require a level of delicacy.

    4     (take) papermaking master Zhou Donghong for example. He uses a fine screen to filter a mixture of water and fibers. He lifts it up, and it’s a sheet of paper. It takes him and his partner only 15 seconds     5     (form) and shape it, but they’ve devoted themselves to     6     (perfect) the skills for decades.

“There are a lot of tricks of filtering the fibers, and timing is     7     (hard) part of all. We have only one chance to filter the right amount of fibers, and only the proper weight guarantees the paper is neither too thin nor too thick, and the margin (差额) for error is extremely small,” said Zhou. With just the right degree of thickness, top quality Xuan paper     8     (hold) ink tightly.

The skill of papermaking,     9     (recognize) as a national treasure, has also proven to be an international one. We felt a great sense of pride as it was listed as a world intangible culture heritage by UNESCO in 2009. Since then, in Jingxian County, Xuan papermaking     10     (teach) in schools.

One summer weekend, my wife, son and I entered a running race on mountain trails (小径). When the race started, our son took off _______, but my wife and I stayed back and ran together, enjoying the scenery. After some time, while running down a narrow, _______ trail, I walked on a big stone and was _______, and in the process, I jammed my toe pretty hard. I realized I’d got my toe _______, but I didn’t take off my shoe and sock to check my _______. Instead, my wife and I kept running.

_______, after going about half the course, I realized my watch on my wrist was _______. Slightly discouraged, I told my wife to go on _______, and I would return to see if I could find it. After running back for some time, I _______ my broken watch off the trail. I picked it up, and quickly put it into my pocket. Then I ________ down the trail. Once I was near the end, I saw my son, who had finished 30 minutes earlier, had run back up the trail to ________ me. He ran with me to the end.

________ it turned out, both my wife and son had won first place in their age groups, but I had no chance of placing. As I sat down to ________ after the race, I decided to take off my shoe and check my toe, and I found that my sock was in blood. Pain and it hurt, but there was a bright side. I ________ to receive any award in my age group, but the race ________ had a special award which was given for the most injured runner in the race.

So, how does this ________ relate to you and me in everyday life? Although everyone wants to live a life of comfort, the ________ is that we often face pain and ________. However, the key to real happiness is ________ pain into something positive. In other words, ________ can make us stronger if we let them.

The wheelchair-bound young man, a patient of mine, was pushed to the lectern at the high school to deliver his commencement address. His face still partially paralyzed, he spoke in a soft voice. But Mark Orsini delivered a powerful speech and received a thunderous applause from his fellow students, who had wondered if he’d live to graduate.

The 18-year-old had developed Guillain-Barre syndrome, which can cause paralysis. Soon he was almost completely paralyzed.

His parents insisted that he was a fighter. He’d get through this and go on to attend Dartmouth. But meanwhile, immobile and on a ventilator (呼吸器), how was he going to ask questions or be involved in his care?

The solution was remarkable: The Orsinis would sit at Mark’s side and recite the alphabet. When they got to a letter Mark needed to spell a word, he’d nod “yes”. They’d write it down, then start over and wait for him to nod again. They never lost patience and Mark was involved with every decision. Standard treatment hadn’t helped, so I proposed a risky procedure to filter (过滤) his blood. After treatment he showed improvement and soon he could move his toes, his legs and then his arms.

Mark has graduated from Dartmouth. I saw him in my office some time ago, and he was feeling great. But there was a lot left unsaid. I wanted to say I was in awe of him, and that his parents were some of the most amazing people I’d ever met, sitting by his bed for hours, patiently listening to their child speak letter by letter. I wanted to tell him of my shame when my children tried to talk to me and I brushed them off because I didn’t have time to listen. I wanted to say I’d never forget him or his parents. But words failed me.

Sarah came running in. “Look what I found.” Over the top of the paper I was reading came a crispy long object that caused me to jump. It was a snake skin that had been shed by one of our many garden snakes.

“Isn’t it beautiful?” said my wide-eyed seven-year-old.

I stared at the organic wrapper and thought to myself that it really wasn’t that beautiful, but I have learned never to appear uninterested with children. They see only good quality and excellence in the world until educated otherwise.

“Why does it do this?” Sarah asked.

“Snakes shed their skin because they need to renew themselves,” I explained. “Why do they need to renew themselves?” Sarah asked.

I suddenly remembered an article on this page many years ago where the writer was expressing her concept of renewal. She used layers of paper over a wall to describe how we hide our original selves, and said that by peeling away those layers one by one, we see the original beneath. “We often need to shed our skins and those coatings that we cover ourselves with,” I said to my now absorbed daughter. “We outgrow some things and find other ones unwanted or unnecessary. This snake no longer needs this skin. It is probably too crinkly（起皱的）for him, and he probably doesn’t think he looks as smart in it as he once did.”

Sarah was getting the point. As we talked, I knew that she began to understand, although slightly, that renewal is part of progress; that we need to take a good look at ourselves, our rooms, schoolwork and creativity, and see what we need to keep and what we need to cast off. I was careful to point out that this is a natural consequence of their growth.

“I see, Dad,” said Sarah and jumped off my lap and ran off.

I hoped she would remember this. That often, in order to find our real selves underneath the layers of community and culture with which we cover ourselves year after year, we need to start examining these layers. We need to gently peel some away, as we recognize them to be worthless or unnecessary; or at best, store the ones thrown away as mementoes（念想）of our promotion to a better vitality or spirit.

Even as Google plans to test its fleet(车队) of self-driving cars on public roads this summer, its business model remains a bit of a mystery. By 2025, as many as 250,000 self-driving vehicles could be sold each year globally, according to a study by an industry research firm.

"Vehicles that can take anyone from A to B at the push of a button could transform mobility for millions of people," said Chris Urmson, director of Google's self-driving car project. For now, Google has no plans to sell any of its self-driving cars. They are strictly for research. But they will hit public roads this summer near Google's headquarters in Mountain View, California. Previous testing has taken place only on closed courses.

The cars are built to operate without a steering wheel, accelerator(油门) or brake pedal. "Our software and sensors do all the work," Urmson said. "The vehicles will be very basic—we want to learn from them and adapt them as quickly as possible—but they will take you where you want to go at the push of a button." The prototypes(雏形) are the first of a 100-car fleet the tech giant is building.

In the long run, Urmson sees a future of safer roads — the majority of auto accidents are caused by human error — and fewer traffic jams. Robotic cars could also shuttle people who can't drive because of age or illness.

Google has said that self-driving cars could launch new business models in which people buy the use of vehicles they don't own. The company has already tested other types of self-driving cars on public streets, including modified Lexus sport-utility vehicles, under a special permit program by the California Department of Motor Vehicles that requires a human driver at the controls.

The state has issued six other companies permits to operate such cars, including Delphi, Mercedes-Benz, Volkswagen, Tesla, Bosch and Nissan. The vehicles that will be tested on open roads this summer will have removable steering wheels, accelerator and brake pedals to allow "safety drivers" to take control if needed.

Google says the cars are safe. The vehicles have sensors that "can detect objects out to a distance of more than two football fields in all directions, which is especially helpful on busy streets with lots of intersections," Urmson said. "We're looking forward to learning how the community understands and interacts with the vehicles, and to uncovering challenges that are unique to a fully self-driving vehicle," Urmson said.