The United States rose to global power on the strength of its technology, and the lifeblood that technology has long been electricity. By providing long-distance communication and energy electricity created the modern world. Yet properly understood, the age of electricity is merely the second stage in the age of steam which began a century earlier.

It is curious that on one has put together a history of both the steam and electric revolutions." writes Maury Klein in his book The Pore Makers, Seam, Electricity and the Men Invented Modern America. Klein, a noted historian of technology spins a narrative (叙述) so lively that at times it reads like a novel

The story begins in the last years of the 18th century in Scotland, where Watt perfected "the machine that changed the world". Klein writes/'America did not invent the steam engine, but once they grasped its passwords, they put it to more uses than anyone else.

Meanwhile, over the course of 19th century, electricity went from mere curiosity to a basic necessity. Morse invented a code for sending messages over an electromagnetic circuit Bell then gave the telegraph a voice. Edison perfected an incandescent bulb (白炽灯泡) that brought electric light into the American home.

Most importantly, Edison realized that success depended on mass electrification, which he showed in New York City. With help from Tesla, Westinghouse's firm developed a system using alternating current (交流电), which soon became the major forms of power delivery.

To frame his story, Klein creates the character of Ned, a fictional witness to the progress brought about by the steams and electric revolutions in America during one man's lifetime. It's a technique that helps turn a long narrative into an interesting one.

George Gershwin, born in 1998, was one of America's greatest composers. He published his first song when he was eighteen years old. During the next twenty years he wrote more than five hundred songs.

Many of Gershwin's songs were first written for musical plays performed in theatres in New York City. These plays were a popular form of entertainment in the 1920s and 1930s. Many of his songs have remained popular as ever. Over the years they have been sung and played in every possible way — from jazz to country.

    In the 1920s there was a debate in the United States about jazz music. Could jazz, some people asked, be considered serious music? In 1924 jazz musician and orchestra leader Paul Whiteman decided to organize a special concert to show that jazz was serious music. Gershwin agreed to compose something for the concert before he realized he had just a few weeks to do it. And in that short time, he composed a piece for piano and orchestra which he called Rhapsody in Blue. Gershwin himself played the piano at the concert. The audience were thrilled when they heard his music. It made him world-famous and showed that jazz music could be both serious and popular.

    In 1928, Gershwin went to Paris. He applied to study composition (作曲)with the well-known musician Nadia Boulanger, but she rejected him. She was afraid that classical study would ruin his jazz-influenced style. While there, Gershwin wrote An American in Paris. When it was first performed, critics (评论家)were divided over the music. Some called it happy and full of life, to others it was silly and boring. But it quickly became popular in Europe and the United States. It still remains one of his most famous works.

    George Gershwin died in 1937, just days after doctors learned he had brain cancer. He was only thirty-nine years old. Newspapers all over the world reported his death on their front pages. People mourned the loss of the man and all the music he might have still written.

Like most of us, I try to be mindful of food that goes to waste. The arugula (芝麻菜) was to make a nice green salad, rounding out a roast chicken dinner. But I ended up working late. Then friends called with a dinner invitation. I stuck the chicken in the freezer. But as days passed, the arugula went bad. Even worse, I had unthinkingly bought way too much; I could have made six salads with what I threw out.

In a world where nearly 800 million people a year go hungry, "food waste goes against the moral grain," as Elizabeth Royte writes in this month's cover story. It's jaw-dropping how much perfectly good food is thrown away — from "ugly" (but quite cat able) vegetables rejected by grocers to large amounts of uneaten dishes thrown into restaurant garbage cans.

Producing food that no one eats wastes the water, fuel, and other resources used to grow it. That makes food waste an environmental problem. In fact, Royte writes," if food waste were a country, it would be the third largest producer of greenhouse gases in the world. "

If that's hard to understand, let's keep it as simple as the arugula at the back of my refrigerator. Mike Curtin sees my arugula story all the time — but for him, it's more like 12 boxes of donated strawberries nearing their last days. Curtin is CEO of DC Central Kitchen in Washington. D.C., which recovers food and turns it into healthy meals. Last year it recovered more than 807, 500 pounds of food by taking donations and collecting blemished (有瑕疵的) produce that otherwise would have rotted infields. And the strawberries? Volunteers will wash, cut, and freeze or dry them for use in meals down the road.

Such methods seem obvious, yet so often we just don't think. "Everyone can play a part in reducing waste, whether by not purchasing more food than necessary in your weekly shopping or by asking restaurants to not include the side dish you won't eat." Curtin says.