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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.

My 13-year-old daughter sent a postcard to us while we were still away on our most recent trip to California. It 1 our house about a week later. The touching 2 nearly brought me to tears.

"Even though we 3 have two days of adventures ahead of us, I am just so 4 for everything we have experienced together on this trip," she writes.

Our youngest daughter is just about to 5 11 years old. In those years, we have never taken a true 6 as a family of four to a place we've never been. Like most 7 , I have no idea where the time has gone. But I also think these are some of the best ages to 8 with kids.

This vacation to California was our very first 9 , long-distance trip together. The kids helped 10 the trip with input on things they might like to see and do. They reached for our hands in crowds. I can't remember the last time they held our hands 11 .

One of our family bonding moments came when we took a family surfing lesson. It was the first time any of us had tried surfing, although it was something the girls had been 12 . The smiles on the girls' faces were everything. They were so 13 when they stood up on the board and rode the waves one by one.

Those are memories I'm going to 14 . And yes, I will remind them of these times the next time I reach for their 15 .

Adults check their phones, on average,360 times a day, and spend almost three hours a day on their devices in total. The problem for many of us is that one quick phone-related task leads to a quick check of our emails or social media feeds, and suddenly we've been sucked into endless scrolling.

It's an awful circle. The more useful our phones become, the more we use them. The more we use them, the more we lay neural（神经的） pathways in our brains that lead to pick up our phones for whatever task is at hand-and the more we feel an urge to check our phones even when we don't have to.

What we do know is that the simple distraction of checking a phone or seeing a notification（通知）can have negative consequences. This isn't very surprising; we know that, in general, multitasking does harm to memory and performance. One of the most dangerous examples is phone use while driving. One study found that merely speaking on the phone, not texting, was enough to make drivers slower to react on the road. It's true for everyday tasks that are less high-risk, too. Simply hearing a notification "ding" made participants of another study perform far worse on a task-almost as badly as participants who were speaking or texting on the phone during the task.

It isn't just the use of a phone that has consequences-its me re presence can affect the way we think.

In one recent study, for example, researchers asked participants to either put their phones next to them so they were visible（like on a desk）, nearby and out of sight（like in a bag or pocket）, or in another room. They were found to perform far better when their phones were in another room instead of nearby-whether visible, powered on or not.

A grandmother was filmed taking notes during a Marvel superhero movie marathon, which at this point includes 30 movies. She wanted to be closer to her1 and talk to them about their2 .

Cheryl Skiados, who is in her 70s, has 13 grandkids3 , aged from 6 to 22, and they're all big Marvel fans. Rather than writing off their interests as silly, as grandparents are 4 doing, she decided to try to get on the same 5 as them.

"I just 6 my grandparents, and I noticed my grandma was making her way through all the Marvel movies," said 18-year-old Jackson. "She was7 them in the order they came out and she asked if I wanted to watch one with her, so of course, I said yes8 ."

"I think it really shows how much she9 her grandchildren, because she is willing to10 there for hours and watch superhero movies, and take notes on them, just so she can have something11 to talk to her grandkids about."

The video has 12 the hearts of many online and racked up(累计) nearly seven million views, and hundreds of thousands of likes, along with it.

"We all 13 Grandma is getting the recognition she deserves for being a(n)14 grandmother," said Jackson.

Skiados, in response to the15 , says she "thinks it's funny," and "her heart was warmed by all the comments."

Let's do something in our daily life for the environment and the earth.

An English teacher has introduced a play to her class.

Characters: Benny, Jerry, Susie, Grace

Time: One Sunday afternoon.

Place: By the river near their houses.

（The four teenagers have just finished the picnic. They are tidying up.）

Benny: Wow! That was a great picnic. I'm so full that I can hardly move.

Grace: That's no excuse for not tidying up, Benny. Come over here and help me pack（包装）up the leftover food. Jerry, please? And clean up the place.

Jerry: （Speaking unhappily to himself.）How can I always get the dirty and difficult jobs? It's not fair.

（Jerry throws a bit of water on the fire. Then he picks up the ashes（灰烬）with an old newspaper and wants to throw them into the long grass.）

Susie: （Sounding surprised）What are you doing, Jerry? That's d....

Jerry: Whoop...the paper has caught fire.

Susie: And the grass…Benny, Grace, help! Help!

（Benny and Grace come over quickly. They help put out the fire completely.）

Jerry: Oh, no. Oh, no! What have I done? 

Grace: You know that we should do everything carefully, don't you? 

Jerry: （With his head in his hands.）Yes. What have I done? What have I done?