Milwaukee, Wisconsin, is road testing a new way to keep winter roads ice-free — by spreading on them cheese brine, the salty liquid used to make soft cheese, like mozzarella.

Wisconsin, also called “America’s Dairyland”, is famous for its cheese. The state produced 2.8 billion pounds of cheese last year! a result, there was a lot of leftover cheese brine. Disposing of(处置)the brine can be expensive. So what should cheese makers do with the waste?

Normally, towns use rock salt to de-ice streets. The salt lowers waters’ freezing point, causing ice to melt (融化). But using cheese brine could help both cheese producers and cities save money, while keeping roads safe. Cheese brine has salt in it, which, like the rock salt, helps lower water’s freezing point.

In addition to saving money, cheese brine could also be a more environment-friendly option. Many people suspect that all the rock salt used every winter is harming the environment.

Rock salt is made of sodium chloride, the sane con-pound (化合物) in ordinary table salt. Sounds harmless, right? But while you probably add only a small amount of salt to your food, road crews spread about 20 million tons of salt on U.S. Roads every year!

The chemical washes off roads and goes into the ground. There it can pollute drinking water, harm plants. and eat away soil. By spreading cheese brine on streets before adding a layer of rock salt, Milwaukee may be able to cut its rock salt use by 30 percent.

Cheese brine has a downside too — a shell similar to that of bad milk. “I don’t really mind it,” Emil Norby told Modern Farmer magazine. He works for one of Wisconsin’s county highway commissions and came up with the idea of using cheese brine. “Our roads smell like Wisconsin!” he said.

A build-it-yourself solar still (蒸馏器) is one of the best ways to obtain drinking water in areas where the liquid is not readily available. Developed by two doctors in the U.S. Department of Agriculture, it’s an excellent water collector. Unfortunately, you must carry the necessary equipment with you, since it’s all but impossible to find natural substitutes. The only components required, though, are a 5＇ ×5＇ sheet of clear or slightly milky plastic, six feet of plastic tube, and a container — perhaps just a drinking cup — to catch the water. These pieces can be folded into a neat little pack and fastened on your belt.

To construct a working still, use a sharp stick or rock to dig a hole four feet across and three feet deep. Try to make the hole in a damp area to increase the water catcher’s productivity. Place your cup in the deepest part of the hole. Then lay the tube in place so that one end rests all the way in the cup and the rest of the line runs up — and out — the side of the hole.

Next, cover the hole with the plastic sheet, securing the edges of the plastic with dirt and weighting the sheet’s center down with a rock. The plastic should now form a cone (圆锥体) with 45-degree-angled sides. The low point of the sheet must be centered directly over, and no more than three inches above, the cup.

The solar still works by creating a greenhouse under the plastic. Ground water evaporates (蒸发) and collects on the sheet until small drops of water form, run down the material, and fall off into the cup. When the container is full, you can suck the refreshment out through the tube, and won’t have to break down the still every time you need a drink.

What is the last step of constructing a working solar still?

As cultural symbols go, the American car is quite young. The Model T Ford was built at the Piquette Plant in Michigan a century ago, with the first rolling off the assembly line(装配线) on September 27, 1908. Only eleven cars were produced the next month. But eventually Henry Ford would build fifteen million of them.

Modern America was born on the road, behind a wheel. The car shaped some of the most lasting aspects of American culture: the roadside diner, the billboard, the motel, even the hamburger. For most of the last century, the car represented what it meant to be American—going forward at high speed to find new worlds. The road novel, the road movie, these are the most typical American ideas, born of abundant petrol, cheap cars and a never-ending interstate highway system, the largest public works project in history.

In 1928 Herbert Hoover imagined an America with “a chicken in every pot and a car in every garage.” Since then, this society has moved onward, never looking back, as the car transformed America from a farm-based society into an industrial

The cars that drove the American Dream have helped to create a global ecological disaster. In America the demand for oil has grown by 22 percent since 1990.

The problems of excessive(过度的)energy consumption, climate change and population growth have been described in a book by the American writer Thomas L. Friedman. He fears the worst, but hopes for the best.

Friedman points out that the green economy(经济)is a chance to keep American strength. “The ability to design, build and export green technologies for producing clean water, clean air and healthy and abundant food is going to be the currency of power in the new century.”