The expression “a thirst for knowledge" may soon have a new meaning for millions of people who have no way to get clean water. Researchers have developed a book with specially treated pages that can turn dirty water into clean and drinkable water. They say their invention could improve the lives of many in the developing world.

    About 700 million people around the world are at risk of disease or even death because their drinking water is not clean. The water is polluted by harmful bacteria.

    The book contains 25 pages. Each page is about one millimeter thick. The pages contain very small particles (微粒) of silver. The pages can be used as filters（过滤器）to remove harmful microorganisms (微生物) that can pollute drinking water. The filter kills the organisms that pass throughit.

    Pictures on the pages show the dangers of dirty water and how to use the book for those unable to read. The pages aremade of filter paper. They are designed to be torn from the book. Water can bepoured through the paper to be cleaned.

    Ms. Dankovich, the inventor, says eachpage can treat up to 100 liters of water. She recently presented her invention at the meeting of the American Chemical Society in Boston, Massachusetts. She was asked whether she had considered adding classic literature on the book's pages.

    "The idea of classic texts—that's of interest maybe later. We have discussed a little bit more exciting text. But we really haven't had the time to go through that part," she says.

    Teri Dankovich and another researcher tested the drinkable book in Bangladesh, Ghana and South Africa. The tests proved to be successful.

    Water for Life, a non-government alorganization, has provided financial support for the project.

    Mosquitoes have an extraordinary ability to find humans far away and fly straight to their skin. Mosquitoes can do more than cause an itchy (发痒的）wound. Some mosquitoes spread several serious diseases, including Dengue, yellow fever and malaria.

    Over one million people worldwide die from these diseases each year. New research now shows how mosquitoes choose who to bite.

    Mosquitoes need blood to survive. They are attracted to human skin and breath. They smell the carbon dioxide gas, which all mammals breathe out. This gas is the main way for mosquitoes to know that a warm-blooded creature is nearby.

    But mosquitoes also use their eyes and sense of touch. Michael Dickinson is a professor at the California Institute of Technology. His research shows how these small insects, with even smaller brains, use three senses to find a blood meal.

    Michael Dickinson's team used plumes—a material that rises into the air of carbon dioxide gas into a wind tunnel (隧道). They then used cameras to record the mosquitoes. The insects followed the plume.

    Then, the scientists placed dark objects on the lighter colored floor and walls of the tunnel. Mr. Dickinson said, at first, the mosquitoes showed no interest in the objects at all. “What was quite surprising is that the mosquitoes fly back and forth for hours. These are hungry females and they completely ignore the objects on the floor and wall of the tunnel. But the moment they get a hit of CO₂, they change their behavior quite obviously and now would become attracted to these little visual blobs (斑点).”

    This suggested to the researchers that a mosquito's sense of smell is more important in the search for food. Once mosquitoes catch a smell of a human or animal, they also follow visual signals.

    It was a shock and a painful lesson for many people when the police announced the cause of a bus accident in Chongqing on Oct 28. Video footage (片段) from inside the bus suggested that after a passenger missed her stop and asked the driver to stop, but he refused. She began hitting him over the head with her cell phone. During the conflict, the driver lost control of the bus and it jumped into the Yangtze River, causing 15 deaths.

    Zheng Chuankai, a lawyer in Beijing, said the accident showed that it was important that those who cause danger to public safety face severe punishment. Such attacks are inhuman but common. In fact, it is not rare to hear of passengers attacking bus drivers in China. This month, a local court in Shenyang, Liaoning province, sentenced three people to up to three years in prison for endangering public safety by distracting bus drivers, Xinhua reported. “Passengers who interfere (妨碍) with bus drivers are endangering public safety, which is equal to serious crimes like arson (纵火) and poisoning.” Liu Changsong，a Beijing lawyer, told the Global Times.

To prevent similar cases from happening, many Chinese cities have taken measures to keep bus drivers safe. Dozens of cities including Beijing, Xi'an, Wuhan, Changsha and Nanning have plans to add safety fences to buses to protect drivers from any interference by passengers.

    The bus operator in Quanzhou, Fujian Province, has invited psychologists to teach drivers how to manage their emotions when facing an angry passenger. These measures are necessary, but they are not enough.

    “Public security is closely connected with social morality (道德). People should obey the law, be more self-disciplined and sensible.”

    Many countries have introduced measures to deal with the problem of violence against bus drivers. On every bus in the US state of New Jersey, a sign on the back of the driver's seat warns passengers that anyone attacking a driver can be fined or put into prison.

    In London, the local government has launched a program to train drivers to deal with angry passengers and avoid potential conflicts.

    Twenty-one years ago, my husband gave me Sam, an eight-week-old schnauzer（雪纳瑞犬）, to help ease the loss of our daughter. Sam and I developed a very special bond over the next years.

    At one point, my husband and I decided to move to a new home in New Jersey. Our neighbor, whose cat had recently had kittens, asked if we would like one. We were a little apprehensive about Sam's jealousy and how he would handle his turf（地盘）being invaded, but we decided to risk it.

    We picked a little, gray, playful ball of Fur. She raced around chasing imaginary mice and squirrels and jumped from table to chair in the blink of an eye, so we named her Lightning.

    At first, Sam and Lightning were very cautious with each other and kept their distance. But slowly, Lightning started following Sam — up the stairs, down the stairs, into the kitchen. Later, when they slept, it was always together; when they ate, it was always next to each other. When I took either one out, the other was always waiting by the door when we returned. That was the way it was for years.

    Then, without any warning, Sam was diagnosed as having a weak heart. I had no other choice but to have him put down. The pain was nothing compared with what I experienced when I had to walk into our house alone. This time, there was no Sam for Lightning to greet and no way to explain why she would never see her friend again.

In the following days, Lightning seemed heart-broken. I could see the disappointment in her eyes whenever anyone opened the front door, or the hope whenever she heard a dog bark.

    One day as I walked into our living room, I happened to see Lightning was lying next to the sculptured replica（复制品）of Sam that we had bought a few years ago, one arm wrapped around the statue's neck, contentedly sleeping with her best friend.

    Scientists have created a scent(气味)-delivery system that releases a pleasant fragrance when you sweat. Apply it to your skin, and the more you sweat, the better you'll smell. That's because the perfume only gets released upon contact with moisture(湿气).

Chemists from Harvard University combined two compounds to create their new system. One chemical is alcohol-based. This is the nice-smelling perfume. The other chemical is an ionic liquid(离子性液体), which is a type of salt that is liquid at room temperature. Ionic liquids are made of ions—molecules(分子) that have lost or gained one or more electrons(电子). If the molecule loses electrons, it will have a positive charge(正电荷). If it gains electrons, it gets a negative charge. Ionic liquids contain the same number of positive and negative ions, which makes them neutral, with no overall electric charge. In general, ionic liquids have no smell.

    When the perfume and ionic liquid are mixed together, a chemical reaction occurs. This bonds the molecules to each other. The reaction also temporarily inactivates the perfume's molecules. So when applied to the skin, the new perfume has no scent in the beginning. But adding water or sweat breaks the bond between the molecules. That releases the scent into the air.

    "The rate of the release of the fragrance depends on how much you sweat, in other words, how much water is available," explains chemist Nimal Gunaratne from Harvard University, who led the research. "Sweat is like the command to let the fragrance go."

    Christian Quellet is a chemist who has worked in the perfume industry for a long time. He is now an independent consultant based in Switzerland. "Gunaratne's perfume opens the door to new developments and applications of fragrance controlled-release systems," he says. Controlled-release systems allow small quantities of some compounds that they hold to enter the environment slowly.

    The system also traps some chemicals in sweat that are responsible for the bad sweat smell. These compounds are called thiols (硫醇). Just as water does, thiols break apart the bond that ties the perfume to the ionic liquid. When this happens, the thiols attach to the ionic liquid and their bad scent is inactivated as the perfume had been. This means the water in sweat and its thiols are both able to release the fragrance from the newly developed perfume.

Effective Ways to Protect Our Planet

We only have one earth. However, humans haven't been very good protectors of the earth over the years. To leave a fine planet for our children and future generations, we all need to take steps to develop better living habits. {#blank#}1{#/blank#}

Buy less. Cheap goods in the sales may make your life better, but few of those are essential. And they almost always end up in the trash can or are forgotten in the back of a. closet. So next time you're hesitating about buying or accepting a non-essential item, think over whether it will truly improve your life. {#blank#}2{#/blank#}

Turn waste into treasure. {#blank#}3{#/blank#} Not only does it keep items out of trash cans, but it can also prevent you from buying new items, which require lots of resources to produce. Moreover, children love making things. So instead of heading towards the craft store, check out your recycling bin first and improve your children's imagination.

{#blank#}4{#/blank#}Did you know it takes over 700 gallons of water to grow enough cotton to make just one plain T-shirt? Instead of going to the mall to buy new clothes, you can consider looking first in a secondhand shop or trading clothes. Second-hand shopping also applies to many other categories of consumer goods such as furniture, cars and children's toys.

Walk, bike or car sharing.According to the Environmental Protection Agency (EPA), a typical passenger vehicle emits (排放) about 4.6 metric tons of carbon dioxide (CO₂) per year. Thus, any amount of what you can cut back on will matter. For short trips, you can try walking or biking. {#blank#}5{#/blank#} If travelling on foot or by bike isn't practical, you can try carpooling with a friend, neighbour or coworker to the same destination.

A. Save water.

B. Choose second-hand stores.

C. If not, it's okay to just say, "No, thanks!"

D. And here are some ways to protect the environment.

E. Plastic bottles are a clear example of waste material.

F. In this way, you can get some exercise without going to the gym.

G. Creating something new with unwanted items is a good way to protect the environment.