【推荐2】Most parts of China have access to sufficient supplies of fresh water for drinking. But fresh water can be in short supply in many regions of the world such as Saudi Arabia, where there are limited water resources. As the world population continues to grow, shortages of fresh water will occur more often and the need for additional water supplies will become critical. Some may ask, “Since the ocean covers more than 70 percent of the Earth, why not just get drinking water from the ocean?”

To turn seawater into fresh water we need to remove the salt in seawater, that is, to desalinate seawater. The problem is that the desalination of water requires a lot of energy. Salt dissolves very easily in water, forming strong chemical bonds, and those bonds are difficult to break. The energy and technology to desalinate water are both expensive, and this means that desalinating water can be costly.

There are environmental costs of desalination as well. Sea life can get sucked into desalination plants, killing small ocean creatures like baby fish, upsetting the food chain. Also, there is problem of what to do with the separated salt, which is left over as a very concentrated salty water. Pumping this super-salty water back into the ocean can harm local sea life. Reducing these impacts is possible, but it adds to the costs.

Despite the economic and environmental hurdles, desalination is becoming increasingly attractive as human beings are using up fresh water from other sources. At present desalinating seawater is the only practical way to provide water to growing populations in rural areas of the Middle East and North Africa. Therefore, the race is on to find a cheaper, cleaner, and more energy-efficient way of desalinating seawater, and promising new finding are being reported.

【推荐3】Over the centuries, through genetic and cultural adaptation, humans and a wild bird species have learned to work together .When human honey-hunters make a certain noise, a bird called the honey guide does its job with unbelievable accuracy, leading people to hidden bees' nests.

Scientists put this ancient practice to the test. When biologists compared the honey guide call to other sounds, the traditional sound sent the honey guides to hidden bees nest three times more often than other sounds, according to a study in the journal Science. When you make the right noise, you end up with more honey compared to the wrong noise.

"It's an exchange of information for skills," said study lead author Claire Spottiswoode, an evolutionary biologist at the University of Cambridge.She failed to find bees nests until her friends made the right noise,and then was rewarded with honey that's very rich and delicious.

The honey guide has a special ability to find bees' nests. “Scientists aren't quite sure how it works, but it likely has to do with a sophisticated sense of smell,” Spottiswoode said. Still, there's a problem: These nests are stuck in trees that are difficult for the birds to reach. Even worse, the bees sting the birds, sometime to death.The people of the region, who make a living on the honey, have tools that can get at those nests and they use smoke to chase the bees away, reducing the stinging problem.

It's clear that the birds have adapted in an evolutionary way through natural selection, but for people the arrangement is probably more cultural.

【推荐1】I like to believe that some things in life never change. A constant, ever since I could hold a pen, has been the routine at lunch with my grandfather. My grandmother will ask me how the walk was from my parents’ house before I take a seat at their kitchen table.

Sitting in his usual spot in the corner is my grandfather. He looks up for a quick “hello” before heading back down to the crossword puzzle in front of him.

“So, how is this one coming along?” I’ll ask. With a failed laugh, he’ll slide the crossword toward me. Carefully cut and neatly folded from his newspaper, three-quarters of it will already have been finished. Many of the clues（线索）are far too advanced for me to figure out. However, I’m happy to help with the strange clue related to sports ---my expert knowledge --- that still remain.

Even if I’m certain of an answer, I fill in the squares with a pencil, as clues are always checked thoroughly by my grandfather. In the rare event that we’re unable to finish the crossword by the end of lunch, he’ll call me later that evening to go over the clues he later solved.

Today, lunch unfolds in its usual manner. However, large parts of the puzzle are blanks “Grandfather, I think this is 49-down... and this, 52-across,” I say.

“Oh, right. Yes, put that down there,” he replies.

I reach across the table to hand him the crossword. Looking at him as he searches for answers, suddenly I feel something different. I note his hair is whiter than I remembered. For the first time I think about my grandfather as, well, a grandfather.

But life is about changes we aren’t always prepared for. Just as we are on different ends of life, we find ourselves on different ends of the city now too. But at lunch, when we take up our pens and open the crossword, the world stands pleasantly still. Now, instead of an exercise of quick wit（机智）, our crosswords are about patience and understanding. As clues are slowly understood, so are the truths in life.

【推荐3】College students constantly hear the praises of education. We have all become used to believing that a college education is always a guarantee of an easier life. I was nine years old when my fourth-grade teacher presented me with a task, to write down all of the things I wanted in my life. I filled my paper with things like: own a big house and have servants; be rich and have a good job. The next day my teacher handed back my paper and in red ink she wrote: “GO TO COLLEGE.” For a long time, I was convinced that once I obtained an education, BAM! Life would be easier.

However, education cannot promise all wishes, dreams, and desires. Society must reject the foolish idea that a college education’s main purpose is to satisfy our desires and secure success. Like most challenging things, education is a gamble (赌博) in which results depend entirely on people’s ability to look past their wants to see the realism and reason behind their wants.

For instance, my first year of college, I took a sociology class. In class, we were taught that Third World countries were poor. We learned that our quality of life would be almost impossible for an average person in those countries. I began to examine my own desire to be rich. To always go after money felt selfish when knowing others had none at all. Learning about other society’s financial situations forced me to look beyond what I wanted.

Through the process of education, everything once desired is tested. Wanting something no longer is enough; it’s more important to examine why we want it and whether we really want it. When my desire for money changed, everything changed. I stopped longing for money-driven careers and stopped valuing the people who had them. I began to examine the things I purchased and my reason for wanting them.

Education is a tool to be used to develop and advance our desires, so we can discover the things that are truly significant in life. Education is a source to expand our society to see beyond the superficial (表面的) appeals and the “quick fixes”, leaving the belief of an effortless life behind in order to desire a meaningful one.