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.

Dear Sir,

    I am writing to express my concern about the plans to build a motorway near our village.

    Haldersham is one of the loveliest villages in England. It is peaceful and quiet, and it is situated in a very attractive valley. There are also several beautiful countryside walks in the surroundings, with a view of many rare trees and plants.

    Most of the people who live in Haldersham have moved here from other places, often from London and other big cities. They have bought houses here to live in a place far away from the noise and the stress of the big city. They paid a lot of money for their houses, but they knew they would get a high quality of life for it.

    If the planned motorway is built, life in Haldersham will change greatly. There will be a lot of noise around us, and nobody will want to go on the walks. House prices will certainly go down, because nobody will want to buy houses in a place close to a motorway. Haldersham will become an ugly place.

    I don't think any of the people living in this beautiful village want that, and we all believe exposure to noise pollution can have a direct influence on our health. So, let's all tell the politicians who support the motorway plans what we think about them!

Yours faithfully,

Hilary Riley

    If your dog looks pleased to see you—it is probably because it loves the particular way you smell.

    The scent (气味)of a familiar human apparently lingers like perfumein the animal's brain—where it causes an instinctive emotional response, research reveals.

    Our scent acts on a part of the canine (犬科的) brain associated with reward and the strongest reactions are produced by humans that pets know best, say scientists in America.

    Gregory Bern, of Emory University in Atlanta, said, “While we might expect that dogs should be highly tuned to the smell of other dogs, it seems that the 'reward response' is reserved for their humans. When humans smell the perfume of someone they love, they may have an immediate, emotional reaction that's not necessarily cognitive (认识的). So is it in dogs. But since dogs have a more sensitive smell than humans, their responses would likely be even more powerful than the ones we might have. In our experiment, however, the owners of the dog were not physically present. The canine brain responses were being caused by something distant in space and time. It shows that dogs' brains have these mental representations of us that persist when we're not there.”

    The experiment involved 12 dogs of various kinds by brain scans while five different scents were placed in front of them. The scent samples (样本)came from the subject (接受试险者) itself, a dog the subject had never met, a dog living in the subject's household. The familiar human scent samples were taken from someone else from the house other than the handlers during the experiment, so that none of the scent donors were physically present.

    The results showed all five scents gained a similar response in parts of the dogs brains involved in detecting smells. Responses were significantly stronger for the scent of familiar humans, followed by that of familiar dogs. The findings showed dogs reacted strongest to the scent of familiar humans even when they were not there. Pets trained as help or therapy dogs showed greater brain activity than the other dogs in the test.

    Researchers say the findings could improve the way to select animals helping wounded old soldiers or disabled people.

    Dolphin or not a dolphin? That is the question! You see, there are several types of dolphins. Some are saltwater dolphins while others are river dolphins.

    "What are the 32 types of dolphins?" When people are asking the question, they are actually referring to the saltwater dolphins in oceans and seas. The river dolphins living in fresh water are not included in these species. But what would be the answer in this case if we ask. "Dolphin or not a dolphin?" The answer would obviously be yes. River dolphins still belong to the dolphin family.

    Among the 32 types of dolphins do not actually wear the word "dolphin" in their names, such as the tucuxi, while others actually have the word "whale" as part of their names even if they are not whales but in fact, belong to the dolphin family, for example, the melon-headed whale and the killer whale. So what would be the answer to the question "Dolphin or not a dolphin?" in these cases? It would be yes. All these species do belong to the dolphin family.

    Another question that people ask is. "Are the sea animals that perform at aquariums(水族馆)all dolphins?" So ,it always seems to come back to the question, "Dolphin or not a dolphin?" Well the answer is no in this case. The sea animals that perform there are not all dolphins. The beluga which people tend to think belong to the dolphin family because they show what seems like a smile, like most dolphins, are in fact a species of the whale family.

    Now that you read these facts about dolphins, you probably realize that certain sea animals may appear to be part of the dolphin species and that others seem to be part of the whale family but in either case, it is not obvious and can be surprising when you identify a sea animal as being a dolphin or not a dolphin. That is the question ！

    The fence was long and high. He put the brush into the whitewash and moved it along the top of the fence. He repeated the operation. He felt he could not continue and sat down.

    He knew that his friends would arrive soon with all kinds of interesting plans for the day. They would walk past him and laugh. They would make jokes about his having to work on a beautiful summer Saturday. The thought burned him like fire.

    He put his hand into his pockets and took out all that he owned. Perhaps he could find some way to pay someone to do the whitewashing for him. But there was nothing of value in his pockets-nothing that could buy even half an hour of freedom. So he put the bits of toys back into his pockets and gave up the idea.

    At this dark and hopeless moment, a wonderful idea came to him. It filled his mind with a great, bright light. Calmly he picked up the brush and started again to whitewash.

    While Tom was working, Ben Rogers appeared. Ben was eating an apple as he walked along the street. As he walked along it, he was making noises like the sound of a riverboat. First he shouted loudly, like a boat captain. Then he said "Ding—Dong-Dong", "Ding—Dong— Dong" again and again, like the bell of a riverboat. And he made other strange noises. When he came close to Tom, he stopped.

    Tom went on whitewashing. He did not look at Ben. Ben stared a moment and then said: "Hello! I'm going swimming, but you can't go, can you? "

    No answer. Tom moved his brush carefully along the fence and looked at the result with the eye of an artist. Ben came nearer. Tom's mouth watered for the apple, but he kept on working.

    Ben said, "Hello, old fellow, you've got to work, hey?"

    Tom turned suddenly and said, "Why, it's you, Ben! I wasn't noticing."

    "Say—I'm going swimming. Don't you wish you could? But of course you'd rather work—wouldn't you? Of course you would."

    Tom looked at the boy a bit, and said, "What do you call work?"

    "Why, isn't that work?"

    Tom went back to his whitewashing, and answered carelessly.

    "Well, maybe it is, and maybe it isn't. All I know is, it suits Tom Sawyer."

    "Oh come, now, you don't mean to say that you like it?

    The brush continued to move.

    "Like it? Well, I don't see why I shouldn't like it. Does a boy get a chance to whitewash a fence every day?"

    Ben stopped eating his apple. Tom moved his brush back and forth, stepped back to look at the result, added a touch here and there, and stepped back again. Ben watched every move and got more and more interested. Soon he said, "Say, Tom, let me whitewash a little."

    Tom thought for a moment, and was about to agree, but he changed his mind.

    "No-no-it won't do, Ben. You see, Aunt Polly wants this fence to be perfect. It has got to be done very carefully. I don't think there is one boy in a thousand, maybe two thousand, that can do it well enough."

    "No——is that so? Oh come, now——let me just try. Only just a little."

    "Ben, I'd like to, but if it isn't done right, I'm afraid Aunt Polly …"

    "Oh, I'll be careful. Now let me try. Say—I'll give you the core of my apple."

    "Well, here—No, Ben, now don't. I'm afraid …"

    "I'll give you all of it."

    Tom gave up the brush with unwillingness on his face, but joy in his heart. And while Ben worked at the fence in the hot sun, Tom sat under a tree, eating the apple, and planning how to get more help. There were enough boys. Each one came to laugh, but remained to whitewash. By the time Ben was tired, Tom sold the next chance to Billy for a kite; and when Billy was tired, Johnny bought it for a dead rat——and so on, hour after hour. And when the middle of the afternoon came, Tom had won many treasures.

    And he had not worked. He had had a nice idle time all the time, with plenty of company, and the fence had been whitewashed three times. If he hadn't run out of whitewash, Tom would have owned everything belonging to his friends.

    He had discovered a great law of human action, namely, that in order to make a man or a boy want a thing, it is only necessary to make the thing difficult to get.

    A Canadian woman who lost her diamond ring 13 years ago while cleaning her garden on the family farm is wearing it proudly again after her daughter-in-law pulled it from the ground or a carrot.

    Mary Grams, 84, said she can't believe the lucky carrot actually grew through and around the diamond ring she had long given up hope of finding. She said she never told her husband, Norman, that she lost the ring, but only told her son. Her husband died five years ago.

    "I feel glad and happy," Grams said this week. "I grew into the carrot. I feel it amazing".

    Her daughter-in-law, Calleen Daley, found the ring while getting carrots in for supper with her dog Billy at the farm near Armena, Alberta, where Grams used to live. The farm has been in the family for 105 years. Daley said while she was pulling the carrots and noticed one of them looked strange. She almost fed it to her dog but decided to keep it when she was washing; the carrots she noticed the ring and spoke to her husband, Grams' son, about what she had found.

    They quickly called Grams. "I told her we found her ring in the garden She couldn't believe it," Daley said. "It was so strange that the carrot grew perfectly through that ring."

    Grams said she wanted to try the ring on again after so many years. With her family looking on, she washed the ring with a little soap to get the dirt off. It moved on her finger as easily as I did when her husband gave it to her.

    "We were laughing," she said. "It fits. After so many years it still fits perfectly."