Reflecting(回忆) on the past about those decisions or actions that can't be reversed(推翻) and being occupied with thoughts of “What if?” is no way to live. But there are a few things in life I'd probably do differently if I had the chance.

    I once majored in architecture — something I had been crazy about for as long as I could remember — and then I suddenly had a change of heart. I made an appointment with my adviser, and told him I was no longer certain I wanted to pursue a career in architecture.

    “Don't give up on your childhood dream!” “He's right,” I thought. “I should just stick it out and I shouldn't disappoint the little girl who once loved architecture.”

    It was awful. I was agonized, holding on to a childhood dream that had long since faded. When I talked with a friend about it a year later, he asked: “Right now, what do you want to do with your life?” That's when I came to the realization that dreams change over time and that you should give up the childhood dream if it's not what you want as an adult. Luckily, it wasn't too late. After some serious thought, I changed my major to journalism. It wasn't something I had always imagined myself pursuing — but at that moment,  it was what I wanted.

    We grow up, and sometimes our dreams change — and that's perfectly OK. You just need to ask yourself every once in a while, “Is this still what I want?” If the answer is no, move on and start chasing a new one.

    A new book called “Battle Hymn of the Tiger Mother” by Amy Chua has caused a debate (争论) about cultural differences in parenting. Amy Chua is a teacher in an American university and both of her parents are Chinese. In the book, Ms. Chua writes about how she taught her daughters. She told NBC television that she had a clear list of what her daughters were not allowed to do, such as having a play date, watching TV or playing computer games and getting any grade less than an A.

    Many people are against Amy Chua's parenting style (风格), even her husband, who is American. They say it is rude and unfair to children. But she says her parents raised her and her three sisters in that way.

    Ms. Chua says after her younger daughter shouted “I hate my life! I hate you!” she decided to retreat because she was afraid of losing her daughter. But she also says American parents often have low expectations of their children's abilities.

    “The debate is about what it means to be a successful parent and what it means to be a successful child,” said Stacy DeBroff, who has written four books on parenting. She says Amy Chua's parenting style is not limited to Chinese families. It is a traditional way of parenting among immigrants (移民). They hope to get a better future for their children.

    She also sees a risk (风险). When children have no time to be social or to develop their own interests, they might not develop other skills that they need to succeed in life. DeBroff advises parents to develop their own style of parenting and not just repeat the way they were raised.

    James Gross, a psychology professor at Stanford University, has a 13-year-old daughter who loves math and science. “It hasn't occurred to her yet that's unusual,” he says. “But I know in the next couple of years, it will.”

    She's already being pulled out of class to do advanced things with a couple of other kids, who are guys. And as someone who studies human emotion for a procession, Gross says, “I know as time goes on, she will feel increasingly lonely as a girl who's interested in math and science, and be at risk of narrowing her choices in life before finding out how far she could have gone.''

    Gross' concern clearly shows what has been a touchy subject in the world of science for a long time: Why are there still so few women in science, and how might that affect what we learn from research?

    Women now make up half the national workforce, earn more college and graduate degrees than men, and by some estimates represent the largest single economic force in the world. Yet the gender gap in science persists, to a greater degree than in other professions, particularly in high-end, math-intensive fields such as computer science and engineering.

    According to US Census Bureau statistics, women in fields commonly referred to as STEM (science, technology, engineering, mathematics) made up 7 percent of that workforce in 1970, a figure that had jumped to 23 percent by 1990. But the rise essentially stopped there. Two decades later, in 2011, women made up 26 percent of the science workforce.

    If humans pump enough carbon dioxide (CO₂) into the atmosphere, the stratocumulus clouds(层积云) could disappear, and the earth's temperature could climb sharply to heights not predicted in current climate models. It would burn the planet. That's the conclusion of a paper published in the journal Nature Geoscience and described in detail by Natalie Wolchover for Quanta Magazine.

    As Wolchover explained, clouds have long been one of the great uncertainties of climate models. Computer models that easily capture the complexity and detail of most climate systems just aren't powerful enough to predict worldwide changes in cloud behavior. But clouds are important. They reflect sunlight away from the earth's surface. And stratocumulus clouds are those white blankets you might have seen as you looked out the window of arm airplane, rolling out below you and hiding the ground Researchers suspect that certain sudden, past jumps in temperature may have been caused by changes to clouds like these.

    For the new research, scientists modeled just a small patch of sky using a supercomputer. They found that if carbon dioxide levels reach about 1, 200 parts per million(ppm) in the atmosphere, stratocumulus clouds break up. That's a very high carbon dioxide concentration.  Right now, levels have climbed past 410 ppm--a dangerous change from 280 ppm before the Industrial Revolution.

    But humans put more and more CO₂ into the atmosphere every year. If current trends continue, the earth could reach 1, 200 ppm within 100 to 150 years. This could happen if our society doesn't follow through on any of its commitments to reduce emissions(排放), Wolchover reported. And even if it does, the result would be another 8 degrees Celsius of heat added to the global average, on top of the dangerous changes already underway due to greenhouse gases.

    That's an enormous change, and it goes beyond predictions of worldwide ice melt and catastrophic sea level rise. And, once the stratocumulus clouds are gone, Wolchover reported, they likely wouldn't reappear until atmospheric carbon dioxide levels dropped below where they are currently.

    There's still some uncertainty in the data. The 1, 200 ppm figure could change as scientists look into the issue further.

    The European Parliament has approved a law banning a wide-range of single-use plastic items, such as straws and cotton buds by 2021. "Europe is setting new standards, paving the way(铺路) for the rest of the world," the European Commission's vice-president Frans Timmermans, who is responsible for sustainable development, said in a statement.

    The new plans come after the EC found that plastics make up more than 80% of marine litter, which has disastrous effects on wildlife and habitats. The EU parliament notes that because of its slow rate of breaking down, plastic residue(残余) has been found in marine species as well as fish and shellfish - and therefore also makes its way into the human food chain.

    Under the new European law, tobacco companies will be required to cover the costs for the collection of cigarette butts. Manufacturers of fishing tools will also have to pay for the retrieval(找回) of any plastic nets that have been left at sea. There's also a new focus on further raising public awareness, where producers of items such as tobacco filters(滤嘴), plastic cups, and wet wipes will be required to clearly explain to users how to appropriately dispose of them.

    The European Commission first suggested the ban in May, which was approved by member states in October. China last year banned the import of 24 varieties of solid waste, including types of plastic and unsorted paper, putting pressure on Europe to deal with its own waste.

    The World Economic Forum estimates that there are about 150 million tons of plastic in the world's seas. A study published in Science in 2015 suggested that between 5 and 13 million tons more are flowing into them every year. Research shows there will be more plastic than fish by weight in the world's oceans by 2050, which has encouraged policymakers, individuals and companies into action.

    John Blanchard was studying the crowd making their way through the station. He was looking for the girl whose heart he knew, but whose face he didn't, the girl with the rose.

    When reading a book in a Florida library a year before, John became interested not in the contents of the book, but in the notes penciled in the margin (空白处). The handwriting reflected a thoughtful soul and beautiful mind. He discovered the former owner's name in the front of the book: Miss Hollis Maynell.

    He located her address and wrote a letter introducing himself. The next day he was shipped overseas to serve in the army. During the next year, they grew to know each other through the mail and their friendship developed. John requested a photograph, but she refused, saying if he really cared, it wouldn't matter what she looked like. When the day finally came for him to return home, their first meeting was suggested-7:00 pm at the Grand Central Station in New York.

    She wrote, "You'll recognize me by the red rose I wear on my coat." So now John was in the station to meet the girl with a rose.

    As a pretty and slim girl in green came over, John noticed her blue eyes like flowers in spring. He walked directly towards her, entirely forgetting she was not wearing a rose. As John came closer to her, he saw another woman with a red rose stood nearby. Well past 40, this woman had graying hair done under a worn hat. Seeing the girl in green walk quickly away, John felt as if he were split (劈开) in two. He desired to follow that girl, but longed for the woman whose spirit had truly companioned and supported him.

    The woman looked gentle and sensible. John went to her, saying, "I'm Captain John Blanchard. You must be Miss Maynell. I am glad to meet you here. May I take you to dinner?"

    She replied with a smile, "I don't know what this is about. But the lady in green who just went by, begged me to wear this rose on my coat. She said if you asked me out to dinner, I'd tell you she is waiting for you in the big restaurant across the street. She said it was some kind of test!"