You may use banknotes every day. But did you know that there is a lot of science behind the money? {#blank#}1{#/blank#}

    Australia was the first country to use polymer(聚合物）banknotes in 1988. {#blank#}2{#/blank#}

They can stop water from making them wet. They are also cleaner because bacteria don't grow easily on them.

Now, the Australians have improved their banknotes again by creating a new 5-dollar note. The new one has a clear window in the middle in which there are pictures of an Australian bird and a building. {#blank#}3{#/blank#}

    Tilt (倾斜）the note a little and you will see the bird flapping its wings as if trying to fly away. Turn the note from side to side and you will notice the building come to life and spin. While these features are impressive and entertaining, that was not the reason why the Australian Government spent ten years perfecting them. Their primary purpose was to make it impossible to fake a banknote.

    {#blank#}4{#/blank#} The new $ 5 bill now has a raised bump alongside the two long edges, enabling the blind or those with limited vision, to quickly determine its value.

The Australian government will give the new 10-dollar note the same features in a year's time. {#blank#}5{#/blank#}

A. Note makers still have a long way to go.

B. Other notes will have them in the future.

C. The magic of the new features lies in them.

D. They have many advantages over paper notes.

E. The new Australian 5-dollar note is a good example.

F. The new note is also the first touchable Australian banknote.

G. Their material and pattern set them apart from ordinary banknotes.

    Antaretica's ice-white environment is going green and facing other unexpected threats. Scientists say that as temperatures go up in the polar region, invading (入侵) plants and insects, including the flies, cause a major conservation threat.

    More and more of these invaders, in the form of larvae (幼虫) or seeds, are surviving in coastal areas around the South Pole, where the temperature has risen by more than 3℃ over the past three decades. Glaciers have retreated, exposing more land which has been occupied by mosses that have been found to be growing more quickly and thickly than ever before-providing potential green homes for invaders.

    “The common house flies are a perfect example of the problem the Antarctic now faces from invading species,” said Dominic Hodgson of the British Antarctic Survey. “It comes in on ships, where it exists in kitchens and then at bases on the continent. It now has an increasing chance of surviving in the Antarctic as it warms up, and that is a worry. Insects like the house flies carry bacteria that could have a deadly effect on native lifeforms.”

    The Antarctic has several native species of insects. Together with its native mosses, these are now coming under increased threat from three major sources: visiting scientists, increasing numbers of tourists and global warming. However, it is global warming that is the main driver of the greening of Antarctica.

    In 2015, more than 38,000 tourists visited Antarctica. “These tourists are often very careful about not leaving waste or having mud. But they could carry seeds or larvae on their boots when they set foot on the Antarctic,” said Hodgson.

    More and more invasive insects and plants have been found on the Antarctic and have required removal. “the insects and plants that are native to Antarctica have survived these for thousands of years,” said Hodgson. “We have got to act now if we want to save the environment.”

    The day will come when renewable energy such as wind, solar, geothermal and others replace fossil fuels as the major source of world energy. However, most analysts insist that this day will not arrive for many decades to come—certainly well past the middle of the century. Systems of fossil fuels have already been firmly set up, and it is too costly or impractical to replace the existing systems with renewables. But there are good reasons to believe that the transition (转变) to renewables will come much faster than previously thought.

    It is hardly surprising that many experts say we will see a relatively slow transition from fossil fuels to renewables, given what is known about previous energy changes of this sort. "Energy transitions take a long time," observed Vaclav Smil of the University of Manitoba in Scientific American. It took more than 50 years for coal to replace wood as the world's leading source of energy and another 50 years for oil to replace coal; the change from fossil fuels to renewables, he argued, is not likely to come any faster.

    Under ordinary circumstances, Smil's forecast would no doubt prove accurate. But these are not ordinary times. Growing concern over climate change is leading to increasingly strict controls on CO₂ and other greenhouse gas (GHG) emissions (排放), while the development in renewables technology is lowering their price and speeding their installation.

    There are, of course, many difficulties in the effective control of carbon emissions, as demonstrated by coal companies to block the introduction of new rules by the US Environmental Protection Agency. Nevertheless, it is impossible to dismiss the progress being made at the local and international levels to promote the use of renewables. The European Union (E. U), for example, is well on the way to achieving a 20% reduction in GHG emissions from 1990 levels by 2020, along with a 20% increase in the use of renewable energy.

    The transition to renewables will be faster due to dramatic improvements in the pricing and performance of such systems. As a result of the steady increases in the efficiency of wind and solar systems, together with the savings achieved through large-scale manufacture, the price of renewables is falling globally. With prices dropping this fast, solar energy is now proving competitive with fossil fuels for generating electricity in many areas.

    The change from fossil fuels to renewable energy will not come overnight, and it will not escape many setbacks. Nevertheless, renewables are likely to replace fossil fuels as the main source of electrical power well before mid-century.

    Mid-afternoon on a particularly busy Tuesday, I took leave of my desk at work and walked into a local Starbucks, only to find a space where neither my clients (客户) nor my children would ask me to do something.

    Inside, I ran into Kate, a co-worker of mine. The topic of parenthood came up. I complained about how packed my schedule was. From the minute I woke up to the minute I fell asleep, I was constantly in demand and always had someone knocking at the door. But a bit of sadness seemed to come over Kate's face.

    "Well, my daughter's in San Francisco and she doesn't seem to need me at all these days." Kate said. It was in that moment that I realized although I might often feel in high demand, there will come a day when I'll actually miss that same stress I now complain about.

    And as our conversation continued, it turned to our children's younger years, with Kate smiling proudly, thinking of the little boy and girl she raised who are now a man and a woman. But I noticed her smile was marked with regret. She explained that she often wondered about what she could have done differently when her children were in their earlier years.

    This got me thinking Is regret an unfortunate footnote (注脚) to parenthood? With that in mind, I asked six older parents one question: What is your biggest regret from your early days as a parent?

    It turned out that all of them thought they could have done it better. But, each of them also has a strong, healthy relationship with their kids. Whatever regrets their parents might have had about their upbringing, one thing is clear—it didn't affect them in a meaningful way.

    The bottom line is, we all feel like we could be doing this parenting thing better, And quite clearly, years later, we're still going to look back and wish we tried things differently. But the past can't be changed, and neither should it.

    Many of us don't pay much attention to the importance of eye care. It is said that if you take care of your body, then you can surely be healthy. That is why our eyes should be given a lot of care. Natural eye care should be put in a number one place.

    There are several causes leading to poor eyesight like having not enough food, genes(基因)and aging(老化). Televisions, computers and reading are also the causes of having poor eyesight. If you happen to work in front of the computer, it is best to take a break every once in a while. You must also try your best to protect your eyes from harmful things. For example, sunglasses are not just for fashion but they can also serve as a great way to protect your eyesight from UV rays.

    Eating healthy food will do good to your eyesight. Remember that vitamins A, C and E are good for eyes. Try to eat food groups that have these vitamins. And you should do eye exercises which can protect your eyesight, too. All above are natural ways of eye care that help us to keep healthy eyes. Being happy all the time can be helpful to a person's eyesight, too. In a word, eye care is very important, no matter how old a person is.

Earth's next superpower

The following countries have been sitting on hidden talents. And now they're about to fly.

NIGERIA (尼日利亚)

Nigeria says it pumps out as much oil as the other two oil-producing countries, Kuwait and Iraq. All this oil is cycling cash into the Nigerian economy and creating extremely rich businessmen. Analysts say that if Nigeria can improve its schools and technology, it could balloon into the world's 13th largest economy by 2050, right between Turkey and Italy. If that reason is not enough for optimism, Nigeria's president also has the sunniest name of any world leader: Goodluck Jonathan.

VIETNAM

As agriculture has given way to industry, unemployment in Vietnam has dropped. What's Vietnam's trick? It's ready to work. Other countries' laborers aren't as cheap as they used to be, which makes Vietnam a relative bargain for companies that need new factories abroad. However, the country has almost no railroads, its highways are in poor condition, and its largest city has just one airport, which was built before the Vietnam War. So what's the use of producing export-ready goods if there's no convenient way to ship them? The good thing is that, however, officials are widening highways, building a new airport and so on.

CHILE (智利)

Pipes, computers, motors, and your microwave all have one thing in common: They're made with copper (铜). Copper makes the world go round. And luckily for Chile, it's got about a third of the planet's copper supply. It just needs a way to dig it up and the government is pouring money into the country's mines.