Since that time, scientists have found that numerous species of fungi produce chemicals to destroy bacteria and that bacteria even produce chemicals that destroy other bacteria. Antibiotics are relatively new in modern medicine, but the earliest medi

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【英语时差8,16】抗生素历史

When you take an aspirin, a decongestant, or a muscle relaxant, the drug youre taking was probably made by a chemist combining a specific mixture of chemicals. Microscopic Fungi And Bacteria Antibiotics, on the other hand, are chemicals produced by m

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【英语时差8,16】土星上真的有生命存在？

Acetylene and hydrogen molecules are disappearing from the atmosphere of Saturns moon, Titan. Its a mystery befitting Sherlock Holmes investigative skills, a mystery NASA scientists hope to crack. About fifty percent larger than Earths moon, Titan is

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【英语时差8,16】伽利略—现代科学之父2

Galileo, however, used one of the earliest telescopes to look at Jupiter. He noticed that Jupiter has moons going around it. Apparently everything in the cosmos didnt have to go around the earth! Perhaps, Galileo said, it just looks like everything m

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【英语时差8,16】伽利略—现代科学之父

What makes Galileo a science hero? For one thing, he moved human knowledge forward against outstanding prejudice and even persecution. Back in 1616, when Galileo argued that Copernicus had been right in suggesting the earth moves around the sun, he w

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【英语时差8,16】微波炉如何加热食物？2

Microwaves heat water by jerking the water molecules around, so to speak. Each water molecule has a slight positive electric charge on one side and a slight negative charge on the other. As microwaves pass by, they exert forces on those charges, firs

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【英语时差8,16】雪会说话？2

Snowflakes are small ice crystals. Snowflakes near the ir melting temperature can, through hand pressure, be made to fuse into a snowball by a process of melting and re-freezing. The snow yields to pressure gently and progressively and doesnt make so

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【英语时差8,16】雪会说话？

Probably all, or nearly all, who have experienced a cold winter, are familiar with the cheery cry of the snow as it is pressed against a hard surface by the steel tire of a wagon, for instance, or even onto a pavement by the heels of ones boots. Thos

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【英语时差8,16】有机蔬菜真的更健康吗？

Every time i go to the grocery stores，i consider buying Organic vegetables because they are supposed to be healthier or something，but they are also moreexpensive. So is it worth it to pay more for the supposed health benefits? Well, it might be w

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【英语时差8,16】空中舞蹈

By bending arms and legs or angling her bodypresenting more or less surface area to the groundshe can change her rate of fall, slowing or speeding up her terminal velocity around ten or twenty miles per hour. To fall as fast as two hundred miles per

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【英语时差8,16】青霉素的历史2

In 1928, Alexander Fleming was studying the bacterium, Staphylococcus, when some of the bacteria became contaminated with Penicillium fungus and stopped growing. Fleming decided that some chemical produced by the Penicillium fungus must be stopping t

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【英语时差8,16】钱能买到一切?2

For example, spending money on things, like a new car or big flat screen TV, may give you a happiness bump at first. But its only temporary. Because we very quickly get used to even our coolest, most expensive possessions and soon barely notice them.

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【英语时差8,16】糖为什么会溶解？

Did you ever wonder why sugar dissolves in a cup of coffee? Why not have the sugar just float in the middle of the cup, without dissipating into the coffee? Its because of the way water molecules interact with molecules in other substances. A water m

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【英语时差8,16】大脑与手2

When people lose a hand, the part of the brain dedicated to that area receives no input at all. It becomes inactive. But the areas around it are still getting signals all the time. Some of those signals seem to leak over into the unused area. Just by

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【英语时差8,16】绿色植物能预知未来？

The scientists guessed that the new seedlings were sensing the presence of neighboring plants by detecting the characteristic color of light reflected sideways from leaves of the neighboring plants. That characteristic color contains a very small amo

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【英语时差8,16】鞋子里的GPS

But measuring movement is actually pretty tricky. Any small mistake in the measured acceleration results in position errors that grow with time. So even if youre standing still and just rocking in place, a navigation computer relying solely on the IM

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【英语时差8,16】钱能买到一切?

or example, spending money on things, like a new car or big flat screen TV, may give you a happiness bump at first. But its only temporary. Because we very quickly get used to even our coolest, most expensive possessions and soon barely notice them.

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【英语时差8,16】谈谈减肥

Why does blowing on hot soup help to cool it off? Its because of evaporation. Evaporation cools down a liquid because the most energetic molecules leap off the surface and leave the slower-moving molecules behind. Slower-moving means lower temperatur

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【英语时差8,16】有机蔬菜真的更健康吗？2

Now, keep in mind that the re may be other reasons to buy organic vegetables. Some people prefer the taste. And because pesticides and fertilizers can pollute rivers and contribute to dead zones in oceans, using less of these chemicals is good for th

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【英语时差8,16】电子烟真的安全吗？

E cigarettes are battery-powered tubes that look like real cigarettes. But instead of inhaling and getting a lungful of tobacco smoke, you basically suck in vaporized nicotine. According to companies that make e cigarettes, since theres no tobacco sm

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