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With the completion of the Human Genome（基因组）Project more than 20 years ago, and the discovery of the double helix structure of DNA enjoying its 70th birthday last year, you might assume that we know how life works. Think again!

Evolution has a 4bn-year head start on us. However, several aspects of the standard picture of how life works-the idea of the genome as a blueprint, of genes as instructions for building an organism, of proteins as precisely tailored molecular（分子）machines and more-have wildly reduced the complexity of life. 

In the excellent book How Life Works, Philip Ball explorers the new biology, revealing life to be a far richer, more delicate affair than we have understood. Ball explains that life is a system of many levels-genes, proteins, cells, tissues, and body modules-each with its own rules and principles, so there is no unique place to look for an answer to it. 

Also, How Life Works is a much more appealing title than the overused question of "What is life?". We should be less concerned with what a thing is, and rather more focused on what a thing does. Defining a living thing implies an unchangeable ideal type, but this will run counter to the Darwinian principle that living things are four-dimensional, ever changing in time as well as space.

But it's an idea that is deeply rooted within our culture. Ball points out that we rely on metaphors（比喻）to explain and explore the complexities of life, but none suffice. We are taught that cells are machines, though no machine we have invented behaves like the simplest cell; that DNA is a code or a blueprint, though it is neither; that the brain is a computer, though no computer behaves like a brain at all.

Ball is a terrific writer, pumping out books on incredibly diverse subjects. There's a wealth of well-researched information in here, and some details that are a bit chewy for the lay reader. But the book serves as an essential introduction on our never-ending quest to understand life.

Earlier this year Rodney Smith Jr. made headlines when he drove eight hours from his home in Huntsville. Alabama, to cut the lawn for an elderly soldier in North Carolina who couldn't find anyone to help him with his yard work.

That wasn't the first time the twenty-nine-year-old Bermuda native had gained such attention. To do his good deeds, Rodney often finds leads for those in need through social media.

Back to one August afternoon in 2015, Rodney Smith Jr. was driving home. That's when Rodney saw an elderly man struggling to mow his lawn. He would take a couple of shaky steps, using the handle to stabilize himself, pause, then slowly push the mower again. Rodney decided to help. Mr. Brown thanked him greatly, and Rodney went home feeling satisfied.

Sitting at his computer to do his homework, Rodney couldn't get Mr. Brown out of his mind. There must be many Mr. Browns out there. He went online and posted that he would mow lawns for free for senior citizens. Messages flooded in.

One day a cancer-battling woman said she wasn't having a good day. Rodney decided to do more than mowing lawns. After he finished mowing, he knocked on her door. "You're going to win this fight, Madam", he said. Then he asked folks to pray for her on social media.

Word of Rodney's mission spread. A grandmother in Ohio said he'd encouraged her 12-year-old grandson to mow lawns. He got a letter from a seven-year-old boy in Kansas. "Mr. Rodney, I would like to be a part of your program, and I'll make you proud," he wrote.

That gave Rodney an idea. In 2017, he decided to establish a programme Raising Men Lawn Care Service to make a national movement for young people. The kids learn the joy of giving back.

Yard work seems like a small, simple thing, but taking care of the lawn means a lot to the people they do it for. "When we mow their yards for free, they can use the money for healthcare and food etc. It means more than you would think," Rodney said.

As an only child, Nicole Renae often felt lonely in her youth. But that all changed when she turned ten. For her birthday, Renae's grandmother 1 her with an adorable gray 2 named Chloe.

From the very start, the two were 3 . "She was my best friend," Renae said. Every ounce of love Renae gave, the little dog returned tenfold.

But when Renae was 14, her father 4 a new job that came with a shocking warning: He'd be working at home, and the house needed to 5 noise disturbance.

"Chloe was very noisy," Renae said. "I was just a kid, so I didn't have any 6 in the matter. I didn't want to 7 my dog. I just felt so sick and 8 about it. With no easier option, the family sent Chloe to a humane society.

9 , Renae grew up, got married, and had a child of her own. But her family didn't feel quite complete. Remembering the 10 that having a dog had brought her as a kid, Renae wanted her daughter to 11 the same. She had it in her mind that she would 12 a puppy, but then one day she saw a post on a social media platform about a 13 dog that needed a new home. The dog in the photograph looked a lot like Chloe —she was even named Chloe. In an instant it was 14 : She would adopt this older dog.

When she met Chloe, the dog seemed so familiar. And Chloe appeared to feel the same 15 about Renae. Soon Renae cried with excitement because she felt so lucky to have Chloe again.

The famous Spanish painter Pablo Picasso once said, "I am always doing that which I cannot do, in order that I may learn how to do it." It strikes a chord(引起共鸣) with me because that's exactly what I have been doing these years.

One of my earliest memories of doing before learning is baking scones(烤饼) when I was about 10 years old. I wanted to bake them to surprise my mother when she returned home.

Before that, I'd observed how my mother baked them many times. As I started to try, I didn't know I shouldn't handle the dough(面团) with my hands too much once I'd added the baking powder(发酵粉). However, I knew exactly how to roll out the dough and use a cookie cutter to cut the scones, because my mom had already taught me.

By the time my mom arrived home, the smell of freshly baked scones welcomed her into the kitchen. They were close to perfection—flat, as a result of overhandling the dough, but they tasted OK. My mom sweetly praised me for my attempt, rather than scolding me for the state of the kitchen, which was like a tornado had just blown!

Have my attempts always been successful? I wish! Some of my kitchen disasters were so terrible that even the dogs wanted nothing to do with them. My gardening failures didn't live to see another season.

But my habit of doing before learning is still helpful. Whatever new software I have to learn how to use, I do so by simply starting to use it. I do, learn, and improve. So if you ask me whether I regret that I tend to do first and learn later, I'd say I don't, because what I have discovered from those is the wisdom to know when it's OK to do and then learn, and when it's probably better to learn and then do!

Discovering a hobby can lead to amazing results, as Maria Martinez, an 11-year-old with a heart of gold, has proven.

Just over a year ago, Maria came across the world of clothes-making, thanks to one of the Christmas gifts she received. Little did she know that this newfound ability would become a source of joy and purpose, not just for her, but also for countless furry friends.

"I got a gift permitChristmas to start clothes-making lessons," Maria said. "I really liked it."

After mastering the basics, an idea came to her mind during a visit to a local exhibition. Surrounded by pet owners and their pets, Maria had an idea that would change lives. Why not create lovely bandannas (头巾) for dogs and cats and use them to support animal shelters?

With great interest and the support of her grandmother, Maria turned a corner of their home into a busy working room. Together, they made many beautiful bandannas, each one filled with love and care.

But Maria's wish went far beyond creating decorations. She began donating her works to shelters like Claws Forever in Fall River, hoping to catch the eye of some people who can take these dogs and cats home.

Maria also began selling them through word-of-mouth and at various events. "At first she started just donating the bandannas because it took her much time to make them. Then she got more skilled and was able to buy cloth with some extra income that she was making from it," her mom, Crystal, said. "Maria is a really kind giving person and she doesn't want for much of anything. It makes her feel good to donate. We are proud of her." Ranging from $3 to $7, money from her sales is now donated to shelters, too. A few weeks ago, she donated more than $200 to the Kingston Animal Shelter.

"They were happy and really grateful, which made me feel really good inside," said Maria. "It makes me happy to see how it's impacted the people and dogs."

In 2014, Amy collapsed from a brain hemorrhage (脑溢血) while working. After a year recovering at home, she 1 a course with the ambition to become a 2 .

However, occasional vision disturbance was still 3 , influencing the amount of 4 she could give to the course. Further complications (并发症) left the young artist almost completely blind, making it difficult to see a whole figure. It's particularly 5 because it seemed to 6 her optimism to be a painter! 

One morning, when watching the sunrise, she suddenly felt a sense of 7 . She realized that she may not 8 a whole face anymore, but it shouldn't stop her from putting what she could see on canvas (画布). The following years, she 9 her special art journey.

"Strangely, my experience has increased my 10 when drawing, enabling me to catch a character better," she explains. "People often speak highly of the detail and sensitivity of the character. I have more determination and appreciation for my 11 . These are 12 I wouldn't have had without everything I've 13 ." For her new touring exhibition, she has produced a series of artworks based on her visual experience. "In the 14 interaction between what I can and cannot see lies my perspective on the world."

Sometimes, we can turn a loss into a gain: something unique and individual that has been gifted to us by never 15 .