2020 年 12 月大学英语四级考试真题（第 3 套）

The things people make, and the way they make them, determine how cities grow and decline, and influence how empires rise and fall. So, any disruption to the world's factories __26__. And that disruption is surely coming. Factories are being digitised, filled with new sensors and new computers to make them quicker, more __27__, and more efficient.

Robots are breaking free from the cages that surround them, learning new skills and new ways of working. And 3D printers have long __28__ a world where you can make anything, anywhere, from a computerised design. That vision is __29__ closer to reality. These forces will lead to cleaner factories, producing better goods at lower prices, personalised to our individual needs and desires. Humans will be __30__ many of the dirty, repetitive, and dangerous jobs that have long been a __31__ of factory life.

Greater efficiency __32__ means fewer people can do the same work. Yet factory bosses in many developed countries are worried about a lack of skilled human workers—and see __33__ and robots as a solution. But economist Helena Leurent says this period of rapid change in manufacturing is a __34__ opportunity to make the world a better place. "Manufacturing is the one system where you have got the biggest source of innovation, the biggest source of economic growth, and the biggest source of great jobs in the past. You can see it changing. That's an opportunity to __35__ that system differently, and if we can, it will have tremendous significance. "

A growing number of U. S. bike riders are attracted to electric bikes for convenience, health benefits and their fun factor. Although ebikes first appeared in the 90s, cheaper options and longer-lasting batteries are breathing new life into the concept.

Established bike companies and startups are embracing ebikes to meet demand. About 34 million ebikes were sold worldwide last year, according to data from eCycleElectric Consultants. Most were sold in Europe and China, where the bikes already have exploded in popularity. Recently, the U. S. market has grown to 263,000 bikes, a 25% gain from the prior year.

The industry is benefiting from improved batteries as suppliers over the years developed technology for laptops, smartphones and electric cars. In 2004, the price of batteries used on ebikes fell, spurring European sales.

But lower cost options are emerging, too. This month, three U. S. bike-share companies, Motivate, LimeBike and Spin, announced electric bicycles will be added to their fleets. New York-based Jump Bikes is already operating an electric bikeshare in Washington, D. C., and is launching in San Francisco Thursday. Rides cost $ 2 for 30 minutes.

The system works like existing dockless bike-share systems, where riders unlock bikes through a smartphone app. "This is the beginning of a long-term shift away from regular pedal (踏板) to electric bikes," said Jump Bikes CEO Ryan Rzepecki. "When people first jump on an ebike, their face lights up. It's exciting and joyful in a way that you don't get from a regular bike. "

Two years ago, CEO Chris Cocalis of Pivot Cycles, which sells high-end mountain bikes, found that U. S. bike shops weren't interested in stocking ebikes. Some retailers warned Cocalis that they'd drop the brand if it came out with an electric bike.

Now that sales are taking off, the vast majority of bike dealers are asking Cocalis when he'll make an ebike available. "There's a tremendous opportunity to get a generation of people for whom suffering isn't their thing," Cocalis said. "Ebike riders get the enjoyable part of cycling without the massive suffering of climbing huge hills. "

The terms "global warming" and "climate change" are used by many, seemingly interchangeably. But do they really mean the same thing?

Scientists shaped the history of the terms while attempting to accurately describe how humans continue to alter the planet. Later, political strategists adopted the terms to influence public opinion. In 1975, geochemist Wallace Broecker introduced the term "climate change" in an article published by Science. In 1979, a National Academy of Sciences report used the term "global warming" to define increases in the Earth's average surface temperature, while "climate change" more broadly referred to the numerous effects of this increase, such as sea-level rise and ocean acidification (酸化).

During the following decades, some industrialists and politicians launched a campaign to sow doubt in the minds of the American public about the ability of fossil-fuel use, deforestation and other human activities to influence the planet's climate.

Word use played a critical role in developing that doubt. For example, the language and polls expert Frank Luntz wrote a memo encouraging the use of "climate change" because the phrase sounded less scary than "global warming," reported the Guardian.

However, Luntz's recommendation wasn't necessary. A Google Ngram Viewer chart shows that by 1993 climate change was already more commonly used in books than global warming. By the end of the next decade both words were used more frequently, and climate change was used nearly twice as often as global warming.

NASA used the term "climate change" because it more accurately reflects the wide range of changes to the planet caused by increasing amounts of greenhouse gases in the atmosphere.

The debate isn't new. A century ago, chemist Svante Arrhenius started one of the first debates over the potential for humans to influence the planet's climate. Arrhenius calculated the capability of carbon dioxide to trap heat in the Earth's atmosphere, but other chemists disagreed. Some argued that humans weren't producing enough greenhouse gases, while others claimed the effects would be tiny. Now, of course, we know that whatever you call it, human behavior is warming the planet, with grave consequences ahead.