6 . The Biggest Stadiums in the World

People have been pouring into stadiums since the days of ancient Greece. In around 80 A.D., the Romans built the Colosseum, which remains the world’s best known stadium and continues to inform contemporary design. Rome’s Colosseum was 157 feet tall and had 80 entrances, seating 50,000 people. However, that was small fry compared with the city’s Circus Maximus, which accommodated around 250,000 people.

These days, safety regulations-not to mention the modern sports fan’s desire for a good view and comfortable seat — tend to keep stadium capacities (容量) slightly lower. Even soccer fans tend to have a seat each; gone are the days of thousands standing to watch the match.

For the biggest stadiums in the world, we have used data supplied by the World Atlas list so far, which ranks them by their stated permanent capacity, as well as updated information from official stadium websites.

All these stadiums are still functional, still open and still hosting the biggest events in world sport.

·Rungrado 1st of May Stadium, Pyongyang D.P.R. Korea. Capacity: 150,000. Opened: May 1,1989.

·Michigan Stadium, Ann Arbor, Michigan, U. S. Capacity: 107,601. Opened: October 1, 1927.

·Beaver Stadium, State College, Pennsylvania, U. S. Capacity: 106,572. Opened: September 17, 1960.

·Ohio Stadium, Columbus, Ohio, U. S. Capacity: 104,944. Opened: October 7,1922.

·Kyle Field, College Station, Texas, U. S. Capacity: 102,512. Opened: September 24, 1927.

Kim Cobb, a professor at the Georgia Institute of Technology in Atlanta, is one of a small but growing minority of academics     1     are cutting back on their air travel because of climate change. Travelling to conferences, lectures, workshops, and the like frequently by plane       2    （view） as important for scientists to get together and exchange information. But Cobb and others     3     （be） now questioning that idea pushing conferences to provide more chances to participate remotely, and     4    （change） their personal behavior to do their part in dealing with the climate change crisis. On a website called No Fly Climate Sci, for example,     5    （rough） 200 academics - many of them climate scientists     6     （promise） to fly as little as possible since the effort started two years ago.

Cobb, for her part, started to ask conference organizers who invited her to speak     7     she could do so remotely; about three-quarters of     8     time, they agreed. When the answer, was no, she, declined the     9     （invite）. That approach brought Cobb's air travel last year down by 75%, and she plans     10    （continue） the practice. "It has been fairly rewarding. ", she says, "a really positive change."

8 . I have the same 24 hours in a day as you do, but I have made specific choice that allow me to make the most of every day and still feel happy and relaxed.     1    

Pick the most important.

    2     Focus on spending time that for you is fun and productive. I chose the life of an adviser because I like to work with companies, but don't want the life of a big company CEO. My choices are based on the lifestyle I want.

Combine your activities.

Many people go crazy trying to figure out how to spend time with friends, family, work, play, etc.     3     Find ways to enjoy them in a combined manner. Build your social life around people in your work environment. Find people in your company who share common interests and develop your career (职业) around the people and activities you love.

    4    

You would think learning takes more time from you, but actually there are always new ways of doing things that can save you time on daily tasks, freeing you up for the most important. Always be looking for a new way to gain back an hour here or there.

Lighten up.

The world won't come to an end in most cases just because you left a few things undone. Celebrate progress and keep refining (改进) toward a happy productive existence.     5     Every completion is a small victory that adds up in a big way.

9 . When I was 9, we packed up our home in Los Angeles and arrived at Heathrow, London on a gray January morning. Everyone in the family settled quickly into the city except me. Without my beloved beaches and endless blue—sky days, I felt at a loss and out of place. Until I made a discovery.

Southbank, at an eastern bend in the Thames, is the center of British skateboarding, where the continuous crashing of skateboards left your head ringing .I loved it. I soon made friends with the local skaters. We spoke our own language. And my favorite: Safe. Safe meant cool. It meant hello. It meant don’t worry about it. Once, when trying a certain trick on the beam(横杆), I fell onto the stones, damaging a nerve in my hand, and Toby came over, helping me up: Safe, man. Safe. A few minutes later, when I landed the trick, my friends beat their boards loud, shouting: “ Safe! Safe! Safe!” And that’s what mattered—landing tricks, being a good skater.

When I was 15, my family moved to Washington. I tried skateboarding there, but the locals were far less welcoming. Within a couple of years, I’d given it up.

When I returned to London in 2004, I found myself wandering down to Southbank, spending hours there. I’ve traveled back several times since, most recently this past spring. The day was cold but clear: tourists and Londoners stopped to watch the skaters. Weaving(穿梭)among the kids who rushed by on their boards, I found my way to the beam. Then a rail—thin teenager, in a baggy white T—shirt, skidded(滑)up to the beam. He sat next to me. He seemed not to notice the man next to him. But soon I caught a few of his glances. “I was a local here 20 years ago,” I told him. Then, slowly, he began to nod his head. “Safe, man. Safe.”

“Yeah,” I said. “Safe.”

10 . What is life? Like most great questions, this one is easy to ask but difficult to answer. The reason is simple: we know of just one type of life and it’s challenging to do science with a sample size of one. The field of artificial life-called ALife for short — is the systematic attempt to spell out life’s fundamental principles. Many of these practitioners, so-called ALifers, think that somehow making life is the surest way to really understand what life is.

So far no one has convincingly made artificial life. This track record makes ALife a ripe target for criticism, such as declarations of the field’s doubtful scientific value. Alan Smith, a complexity scientist, is tired of such complaints. Asking about “the point” of ALife might be, well, missing the point entirely, he says. “The existence of a living system is not about the use of anything.” Alan says. “Some people ask me, ‘So what’s the worth of artificial life?’ Do you ever think, ‘What is the worth of your grandmother?’”

As much as many ALifers hate emphasizing their research’s applications, the attempts to create artificial life could have practical payoffs. Artificial intelligence may be considered ALife’s cousin in that researchers in both fields are enamored by a concept called open-ended evolution (演化). This is the capacity for a system to create essentially endless complexity, to be a sort of “novelty generator”. The only system known to exhibit this is Earth’s biosphere. If the field of ALife manages to reproduce life’s endless “creativity” in some virtual model, those same principles could give rise to truly inventive machines.

Compared with the developments of Al, advances in ALife are harder to recognize. One reason is that ALife is a field in which the central concept — life itself — is undefined. The lack of agreement among ALifers doesn’t help either. The result is a diverse line of projects that each advance along their unique paths. For better or worse, ALife mirrors the very subject it studies. Its muddled (混乱的) progression is a striking parallel (平行线) to the evolutionary struggles that have shaped Earth biosphere.

Undefined and uncontrolled, ALife drives its followers to repurpose old ideas and generated novelty. It may be, of course, that these characteristics aren’t in any way surprising or singular. They may apply universally to all acts of evolution. Ultimately ALife may be nothing special. But even this dismissal suggests something：perhaps, just like life itself throughout the universe, the rise of ALife will prove unavoidable.