D

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.

Recently, a 15-year-old girl Lynn Sumpter broke the rules by going to a sleepover party secretly. And her 1 gave her a choice between handing over her phone for a month, or giving them access to her social media for two weeks. She chose the latter and the netizens are so 2 of it.

Lynn Sumpter's social media 3 by her parents, Tawnya Ford and Lary Sumpter, began early in November with an instagram (照片墙) post that 4 she had chosen to abandon her social media for two weeks. So her 5 could expect "some amazing Instagram posts, snapchats and tiktoks from her parents". On November 11, Lynn's dad had already begun his 6 exploration to embarrass his teen daughter, by 7 one of his photos, saying "Felt cute. Might delete later". But that was 8 the beginning. From posing in a tight top and 9 a blonde wig (假发) to dancing around in a pair of shorts and a tank-top (背心), it seemed like there was nothing the 43-year-old wouldn't do to 10 .

Over the course of two weeks, Lynn Sumpter's Instagram following 11 from around 2,700 to 12,700 at the time of this writing, so she should probably thank her parents for their 12 punishment. The only question is "Can she 13 dad Larry's creativity?" She'll have to give it a(n) 14 as many of her social media fans are already 15 her to bring dad back.

    In my early thirties, I decided to climb Mount Kilimanjaro, the highest mountain in Africa at 5, 895meters above sea level. 

    After months of preparation, I started my great 1 . At the base of the mountain, I met Mik, a local porter, who warmly 2 me. Mik's job was to carry my equipment up the mountain, set up the tent, and carry everything back down after reaching the 3 . 

    The first day of the climb was 4 the rain forest, across a slippery , muddy ground covered with tree roots and vines (藤蔓) . Mik was carrying 30 kilos on his head! By that evening, we made it to 3, 000meters. The air was 5 and it was colder. When I arrived at the campsite for the night, my tent was already set up and waiting for me. 

    Day two was much steeper and rockier. I really had to 6 what I was doing. And I felt guilty for the tough 7 Mik had to work in. Yet when I turned to Mik, he said with the biggest smile, "pole, pole, "which means"8 , take it easy" in his native language. I 9 back, my burden lighter somehow. 

    Over the next five days, the climb got 10 difficult. The temperatures could 11 from 21℃to below freezing in a few hours. At 5, 700 meters, there's only half the oxygen 12 in each breath compared to at sea level. That leaves many people with severe headache. Yet Mik always had a smile and a positive attitude. It had an enormous impact on mo, giving me the 13 to keep going. 

    Even today, when I find myself 14 with anything in life, I just think back to Mik and his smile. A great attitude can bring joy to those around you, or even 15 strangers to the top of a mountain. 

Here are two athletes who are masters in their sports and also set{#blank#}1{#/blank#} good example for others.

Lang Ping, as a player, brought honour and glory to her country. As a coach, she led the China women's volleyball team to {#blank#}2{#/blank#} (medal) at world championships and the Olympics. When the Chinese team was preparing for the 2015 World Cup, her {#blank#}3{#/blank#} (determine) was tested. The team she had built was falling apart. Two of her players had to leave.{#blank#}4{#/blank#} (face) the challenge, Lang Ping didn't lose heart. She knew that her young players could win{#blank#}5{#/blank#} they worked together as a team. Two weeks later, they were world champions.

Michael Jordan, who became known as "Air Jordan", changed basketball with his graceful moves and jumps. His skills were{#blank#}6{#/blank#} (impress), but the mental strength he showed made him unique. In the final seconds of a game, Jordan always seemed to find a way {#blank#}7{#/blank#} (win). Jordan says that the secret {#blank#}8{#/blank#} his success is learning from his failures. Losing games taught him to practise {#blank#}9{#/blank#} (hard) than before and never give up. In life, Jordan has learnt to share his success with others. The Boys and Girls Club he started in Chicago {#blank#}10{#/blank#} (help) young people since 1996.