“Sugar, alcohol and tobacco,” economist Adam Smith once wrote, “are commodities which are nowhere necessaries of life, which have become objects of almost universal consumption, and which are, therefore, extremely popular subjects of taxation.”

    Two and a half centuries on, most countries impose (征税) sort of tax on alcohol and tobacco. With obesity levels putting increasing pressure on public health systems, governments around the world have begun to toy with the idea of taxing sugar as well.

    Whether such taxes work is a matter of debate. A preliminary review of Mexico's taxation found a fall in purchases of taxed drinks as well as a rise in sales of untaxed and healthier drinks. By contrast, a Danish tax on foods high in fats was abandoned a year after its introduction, during claims that consumers were avoiding it by crossing the border to Germany to satisfy their desire for cheaper, fattier foods.

    The food industry has, in general, been firmly opposed to such direct government action. Nonetheless, the renewed focus on waistlines means that industry groups are under pressure to demonstrate their products are healthy as well as tasty.

    Over the past three decades, the industry has made some efforts to improve the quality of its offerings. For example, some drink manufactures have cut the amount of sugar in their beverages (饮料).

    Many of the reductions over the past 30 years have been achieved either by reducing the amount of sugar, salt or fat in a product, or by finding an alternative ingredient. More recently, however, some companies have been investing money in a more ambitious undertaking: learning how to adjust the fundamental make-up of the food they sell. For example, having salt on the outside, but none on the inside, reduces the salt content without changing the taste.

    While reformulating (再制定) recipes is one way to improve public health, it should be part of a multisided (多边的) approach. The key is to remember that there is not just one solution. To deal with obesity, a mixture of approaches, which include reformulation, taxation and adjusting portion sizes, will be needed. There is no silver bullet.

Industrial emissions (排放) of carbon dioxide and other planet-warming greenhouse gases have raised the global average temperature by about 0.8℃ since the beginning of the Industrial Revolution. But studies have disagreed about what impact the rise is having on the world's species, says Mark Urban, an ecologist at the University of Connecticut, Storrs. Some have estimated that as many as 54% of species could eventually become extinct as a result of the climate change, but others have suggested no significant impact.①

    Such disparate result might originate from the limited nature of some individual studies, possibly because they focused only on a few species or a relatively small geographical region, says Urban.② To address these limits, Urban used statistical methods to help blend the results of previous studies into an apples-to-apples comparison that estimates the risk of extinction of species worldwide.

    ③He chose to analyze only the results of studies that had assessed extinction risks of more than one species. Then he researched into the details, such as the regions in which species considered, whether those species were limited to one small region or were widely spread, and whether the species were free to move as climate changed or were blocked by barriers such as mountain ranges or urban development.④

    Effects of climate change aren't always immediate, Urban says, and the risks of extinction he's estimated are the long-term results of species not being able to find a suitable habitat. Maybe the habitat will merely shrink to a size that can't support the species, or maybe it will disappear entirely. In some cases, he notes, a species might not be able to outpace the shift in its range, dying out before it can reach a new homeland. For over the generations that rapid warming might kill them off before they can spread to a suitable new habitat.

    A thrilling polar competition between two adventurers to cross Antarctica alone, unsupported and unassisted had a happy ending with both explorers achieving the unprecedented feat (功绩). American professional athlete Colin O'Brady and British Army Captain Louis Rudd set off a mile apart at the same time on November 3, 2018, from the Atlantic coast with the aim to become the first person to ski across the remote continent alone.

    Louis Rudd maintained the lead at first. However, O'Brady caught up with Rudd on November10 and never let the British man get close to him again. O'Brady was the first to conquer the 930 mile icy land, arriving at the Ross Ice Shelf on the Pacific coast by way of the South Pole on December 26, 2018. The 33-year-old spent 54 days skiing the world's coldest continent while pulling a 300-pound sled(雪橇) with supplies.

    Instead of leaving the harsh environment after completing the historic adventure, the explorer set up a tent on the world's largest ice sheet and waited patiently for Rudd to complete the great undertaking. On December 29, just three days after O'Brady arrived, the British explorer finished his adventure, becoming the world's second person to complete the solo crossing of the frozen continent.

Rudd was not disappointed at being second since he never considered it to be a     "race". Besides, the 49-year-old British Army Captain had a more selfless motive for attempting the feat. He was doing it in memory of his friend Henry Worsley, who had introduced him to polar exploration. The disaster happened while Worsley was trying to cross the continent alone in 2016. Rudd said, "I didn't want to get drawn into a race. All that mattered to me was that I completed it, and that I skied solo and unsupported, carrying the flag with Henry's name on it."

    After spending a few days camping 10 feet away from each other, the two adventurers were picked up by a helicopter to the South Pole scientific research station.

    The United States will introduce a new and comprehensive(综合的) exam for students who seek to study in American and other English-speaking countries, Xinhua News Agency reported from New York.

    The exam, which stands for a great change from the current English level test, was disclosed by Theresa Chang Wei Jen, associate director of the International Service of the US College Board, America's leading educational organization.

    The Advanced Placement International English Language (APIEL) will be offered for the first time throughout the world on May 10, 2002, said Jen.

    However, the APIEL is a strange title to most Chinese students, and it is unlikely to soon gain the similarity of other already existing exams, such as the TOEFL(Test of English as a Foreign Language), the GRE(Graduate Record Examination), or the IELTS(International English Language Testing System).

    "I have never heard of such a test and I would prefer the IELTS if I need another exam," said Xu Jingyan, a graduating student from Beijing University of Aeronautics and Astronautics, who wants to study in England and has already taken the TOEFL.

    Most of Xu's classmates have never heard of the APIEL. "The APIEL is designed for international students who wish to get university studies in English-speaking countries, including the United States, Britain, Canada, and Australia." said Jen.

    The APIEL has been adopted, said Jen, because the TOEFL can no longer accurately reflect the abilities of students of using the English language comprehensively in an academic environment. Xinhua reported that a fairly large number of foreign students who earned high scores in TOEFL exam turned out to be very ordinary educational performers after admission.

    Compared with the TOEFL, the APIEL measures a student's ability to read, write, speak and understand English through testing his or her skills in listening comprehension, speaking with accuracy(精确) and resourcefulness, and writing with clarity(清晰) and fluency, Jen said.

    Madame Marie Curie famously won two Nobel Prizes, but many other women have also been awarded the prize, too. Here are their stories.

    Selma Lagerlof

    Selma Lagerlof was a Swedish author and teacher. She published her first novel, Gosta Berling's Saga, at the age of 33. She was the first female writer to win the Nobel Prize in Literature which she was awarded in 1909. Additionally, she was the first female to be granted membership in the Swedish Academy.

    Gerty Theresa Cori

    Gerty and her husband, Carl Cori, met in Prague and lived in Austria before immigrating to the United States in 1922, where the two medical doctors worked together at Roswell Park Comprehensive Cancer Center in New York. In 1947, Gerty and Carl were awarded the Nobel Prize in Physiology or Medicine, making Gerty Cori the first woman to hold the honor.

    Maria Goeppert-Mayer

    In 1942, Maria Goeppert-Mayer joined the Manhattan Project. From there, she moved on to Los Alamos National Laboratory, then to Argonne National Laboratory, where Goeppert-Mayer developed the nuclear shell model. For this, she shared the 1963 Nobel Prize in Physics with J. Hans D. Jensen and Eugene Paul Wigner.

    Dorothy Crowfoot Hodgkin

    Dorothy Hodgkin's mother encouraged her love of science as a child, and at age 18, she began studying chemistry at a women-only Oxford college. Her work on mapping vitamin B12 earned her the Nobel Prize in Chemistry in 1964.

Strategies to Overcome Self-Doubt Once and For All

Being self-confident is not easy and not everyone can do it, but it doesn't need to be that difficult. {#blank#}1{#/blank#}

Going through life can be very challenging at times. When we were young, no one told us how hard it will be in the future but here we are {#blank#}2{#/blank#} And it is unpleasing and can kill your confidence levels if not controlled from the beginning.

We will all experience some self-doubt, which is natural. {#blank#}3{#/blank#} It happens to us during normal days or whenever we are going to start a new job, a new task, or a new relationship, anything new in life will make you self-doubt. This sort of feeling puts you into dark days when nothing seems to go right and you might feel like giving up, and that is the time to be strong.

 {#blank#}4{#/blank#} Self-doubt is when you are unsure about one or more aspects of yourself. For example, when starting a new job, you might feel inexperienced or might think that you are not fit enough for the job, and this is a prime example of self-doubt.

 {#blank#}5{#/blank#} Low-level of self-criticism is actually good for you. It motivates you and pushes you to be better in life, to become greater than yesterday. This type of feeling will push you to work harder and faster than before and will also increase your productivity, but it should be a low level of self-criticism. You don't want to punish yourself over things that are beyond your control.

A. We needn't take it seriously.

B. It's impossible for us to deal with it.

C. One of the big problems of adult life is having self-doubt,

D. Self-doubt isn't all that bad, let us tell you why.

E. Let's explore to find ways to remove self-doubt forever.

F. It will take long for us to solve this problem.

G. There are some people mistaking self-doubt for something else.