I still clearly remember that day. I was on the side of the road for about four hours with my big jeep. I put signs in the windows that said,“Need a jack (千斤顶）.”

    As I was about to give up, a truck stopped and a man got off. He looked at the situation, made a judgment and went back to take a jack. After about two hours, we finished the job with sweats. We were both dirty. His wife took a large bottle of water for us to wash our hands.

    I tried to put $20 in the man's hand, but he wouldn't take it, so I went to give it to his wife quietly. I asked their little girl where they lived. She said they lived in Mexico. They were in Oregon now, so Mommy and Daddy could pick cherries for the next few weeks. After that, they were going to pick peaches and then go home.

    After I said goodbye and started going back to my jeep, the girl ran to me and handed me a tamale(玉米粽子)for lunch. I thanked them again and walked back to my jeep. When I opened the tamale, what did I find inside? My $20! I ran to the truck and the guy rolled down his window. He started shaking his head, smiled and  said in English“Today you, tomorrow me. ” Then he drove away, with his daughter waving to me from the back.

    This family, working on a seasonal basis where time is money, took a couple of hours to help a stranger while others passed by quietly.

    Since then I've helped many people like the Mexican family. I didn't accept their money. Every time I was able to help, I felt as if I was putting something in the bank.

    Of all nature's disasters, forest fires are often considered the most frightening. Moving at lightning speed, huge walls of flames can burn acres of land in just a few minutes. And although technology, including the use of fire-retardant chemicals, has greatly helped the fight against forest fires, they still do great damage.

    According to the National Interagency Fire Center, the fire season last year was the worst on record in terms of the number of fires and acres burned. There were 96. 385 fires and 9.873429 acres affected by fire in a year that was 125% more destructive(毁灭性的) than the10-year average. These fires cost the federal government $1.5 billion to fight, and this figure does not include the money spent by local and state governments as part of the effort.

    Fires in the southern states represented half of the national total last year with Texas, Oklahoma and Arkansas being home to a usually high amount of activity. Wildfire has also taken place in Western states such as California, Colorado and Alaska throughout the past 10 years.

    It is said that two-thirds of forest fires are started accidentally by people. Almost one quarter are purposely set, while lighting causes 10%.

    Forest fires can have advantageous effects. Charcoal(木炭) enriches soil and some plant species(种类) grow well after fire. The cones of the jack pine tree, for example, will not spread their seeds unless there is heat. Douglas fir trees grow best in open sunlight areas after fire.

    The loud noise of the cars or the sound of a plane can force its way into the deepest forest, yet it's not only humans that are bothered by the noise.

    Bioacoustician Bernie Krause has been studying the effect of noise pollution on wildlife, and has come across some interesting behaviors, especially among animals that communicate by sound, like humans. Birds use sound to communicate, but in noisy places, these animals have to shout over the natural noise to be heard.

    Krause mentions a study of nightingales(夜莺) to explain what he means. The birds responded to（回应） traffic noise by singing louder and louder until they actually went beyond noise pollution standards in the city. To belt out (sing loudly) their songs, they increased their lung pressure fivefold, but scientists say that this is not dangerous for the birds themselves.

    Studies show that sudden noise can cause certain birds to leave their nests, leaving the young to their enemies. One study also showed that songbirds that nested close to busy motorways were much less productive than those that nested farther away. Mammals（哺乳动物）too are affected(影响). A recent study showed that nursing caribou（驯鹿） responded to plane noise by not producing enough milk to feed their young.

    In some cases noise pollution can actually help some animals while harming others. Toads（蟾蜍）and frogs are known to sing in union（同步发声）so that no predator (their enemies) can catch them. Krause found that when planes flew overhead and disturbed the toad's song, they lost their union, and it took them 45 minutes to get it back again. That gave their natural enemies plenty of time to find and catch individual toads by sound.

    According to Kruse, 'Not only will noise pollution bother wildlife, but it won't help our lives either.'

    Time flies, but the tracks of time remain in books and museums. This is what made a recent tragedy in Brazil even more terrible.

    On Sept.2, a big fire ripped through the National Museum of Brazil.“ Two hundred years of work, research and knowledge were lost,” Brazilian President Michel Temer wrote on Twitter after the fire. “It's a sad day for all Brazilians.”

    Most of the 20 million pieces of history are believed to have been destroyed. Only as little as 10 percent of the collection may have survived, Time reported. Among all the items, there were Egyptian mummies, the bones of uniquely Brazilian creatures such as the long－necked dinosaur Maxakalisaurus, and an 11,500－year－old skull called Luzia, which was considered one of South America's oldest human fossils.

    Besides these, Brazil's indigenous(本土的，土著的) knowledge also suffered. The museum housed world－famous collections of indigenous objects, as well as many audio recordings of local languages from all over Brazil. Some of these recordings, now lost, were of languages that are no longer spoken.

    “The tragedy this Sunday is a sort of national suicide, a crime against our past and future generations,” Bernard Mello Franco, one of Brazil's best－known columnists, wrote on the O Globo newspaper site.

    The cause of the fire is still unknown, as BBC News reported on Sept. 3. After the fire burned out, crowds protested outside the museum to show their anger at the loss of the irreplaceable items of historical value.

    According to Emilio Bruna, an ecologist at the University of Florida, museums are living, breathing stores of who we are and where we've come from, and the world around us.

    Just as underwater grass floats on the surface if it loses its roots, a nation is lost without its memories. The fire at the National Museum of Brazil teaches the world an important lesson: We should never neglect history.

    The earliest known copy of Leonardo da Vinci's Mona Lisa—thought to have been painted at the same time as the original masterpiece—has been discovered at the Prado Museum in Madrid, Spain. The work offers art-lovers an attractive clue to what the model for the world's most famous painting really looked like. Controllers of the museum found the picture hidden beneath layers of paints during restoration work on a picture initially thought to have been a later replica(exact copy) of the Mona Lisa.

    The restored version shows the same woman that Leonardo depicted (描画), against a landscape similar to that shown in the background of the original, which now hangs in the Louvre in Paris. And while the features of Leonardo's Mona Lisa have been dulled by centuries of dirt and layers of cracked paints—which are unlikely ever to be removed—in the recently-rediscovered copy, she appears fresher-faced and younger than her better-known "twin".

    News of the find was revealed at a meeting at London's National Gallery, linked to its "Leonardo da Vinci: Painter at the Court of Milan" exhibition. "This sensational (轰动的) find will transform our understanding of the world's most famous picture," the Art Newspaper reported, adding that the clues found on the Madrid version suggest that the original and the copy were begun at the same time and painted next to each other, as the work went on.

    Miguel Falomir, manager of Italian painting at the Prado, told reporters that expert analysis suggested a strong link between Leonardo and the artist who painted the copy. "The painting was done in the painter's own workshop," he said. "It is absolutely consistent with Leonardo's work, but Leonardo didn't actually do any work on it himself."

When bicycle-sharing company oBike pulled out of Singapore abruptly last year, it left the city with unattended bicycles everywhere. Myanmar businessman Mike Than Tun Win saw the perfect opportunity to turn trash (垃圾) into treasure. "What if these bicycles could be distributed to poor students in villages so they can cycle to school? " he thought.

Mr Than, 33, grew up in Mandalay, where he used to walk to school as a student. While traveling through rural (乡村的) areas in Myanmar over the last few years he saw things had not changed. Long lines of children in rural villages continue to walk 30 minutes to an hour just to get to school. "I thought if we could just reduce the time they take, they could spend more time studying, gain more knowledge and increase their chances of getting out of poverty (贫困), " he said.

With that, he started a movement called Lesswalk with the intention of buying bicycles from bike-sharing firms oBike and ofo—which have stopped operations in Singapore — and shipping them to Yangon. He would renew the bicycles before distributing them to teenagers and families living in rural villages in Myanmar, beginning with villages in Mandalay and Sagaing areas.

Over the last three months, the businessman has bought 10, 000 bicycles in Singapore and Malaysia. He paid for 5, 000 of the bicycles out of his own pocket, with other sponsors paying for the rest.

Mr Than plans to modify (修改) the bicycles so that they can better suit the needs of the children in villages. Most of the time they ride around with their little brothers and sisters. "I'm planning to add an extra seat at the back so that they can go to school together," he said. He also plans to remove the digital locks and give each a new one that works better in villages.

Including the cost of shipping, modification and distribution, Mr Than thinks each bicycle might cost him around US $35 to US $40. "I might have to spend more money, but it is better that these bicycles are going to help some people rather than going to waste," he said.