Do you ever wonder why trees begin to bud (发芽) earlier in some cities? Scientists finally found the answer but it's not very pleasant. New science suggests a relationship between light pollution and the timing when trees produce buds, which signals the arrival of the spring season.

    Light pollution is defined by the Lighting Research Center as the unwanted consequence of outdoor lighting such as street lights. Excessive (过多的) man-made light at night results in disturbed natural cycles, and also prevents the observation of stars and planets at night. But its effect on the environment goes beyond that.

    By studying some trees, researchers found out that trees that are more exposed to artificial lighting at night bud up to 7.5 days earlier than those at the natural nighttime setting. And they found out that light had a more significant effect than temperature when the buds came out. The early budding may cause problems for insects, which feed on leaves, and the birds which then feed on them in turn. Professor Richard Ffrench-Constant, who helped lead the research, explained that more than the budding of trees, the study implies the danger to the balance of the ecosystem. “At the moment, caterpillars (毛毛虫) are timed to hatch to make the most of the opportunities to feed on freshly budded leaves, and birds hatch in time to feed on the young caterpillar,” he said.

    Migratory (迁徙的) birds are also negatively affected by light pollution. The glare might confuse them and make them lose their flying sense. The phenomenon might explain why some birds accidentally knock into buildings.

    Such results stress the need to pursue studies that aim to measure the effect of light pollution. If the issue were left to continue, it is estimated that by 2100, spring would begin almost a full month earlier than it does today.

    If you are taking vitamin supplements to reduce your risk of heart disease or cancer, a group of health experts want you to know that those vitamins may actually increase your risk of cancer.

    The US Preventive Services Task Force came to this conclusion after reviewing dozens of studies.

    Nearly half of adults in the US take at least one vitamin or mineral supplement on a regular basis. These pills are advertised as a way to promote general health. In some cases, manufacturers promote them as cancer fighters and heart protectors.

    Studies in animals and in laboratory dishes suggest that oxidative(氧化性的) stress contributes to diseases like cancer and heart disease. If so, there is a reason to believe that antioxidants—including beta-carotene, vitamins A, C, and E—could be useful as preventive medicines.

    But when the Task Force examined the medical evidence on vitamins, it found “inadequate(不充分的) evidence” to support the claims that vitamin and mineral supplements benefit healthy adults.

    “Cardiovascular(心血管的) disease and cancer have a significant health impact in America, and we all want to find ways to prevent these diseases,” Dr. Virginia Moyer, who heads the Task Force, said in a statement. But so far, she added, the medical evidence does not show that taking vitamins is helpful in this regard.

    However, the Task Force did find “adequate evidence” that people with a raised risk for lung cancer actually increase their risk further by taking beta-carotene, a precursor of vitamin A.

    The Task Force recommendations of taking vitamins regularly apply to healthy adults aged 50 and older who don't have “special nutritional needs”. The advice does not apply to children, women who are pregnant or may become pregnant, people with chronic illnesses, or people who have to take supplements because they can't get all their essential nutrients from their diet.

    “Why do birds sing?” I asked a group of children. “To attract metes(配偶)!” answered a boy. A 4-year-old girl added shyly, “birds sing because they are happy, and they want to make us happy, too.” I think both answers are probably true in a way. If birds sing happily, it shows all is well in the forest: no predators (捕食者) are present, and the birds can feed, sing and do other bird things. The sound of a relaxed robin(知更鸟) singing is easy to understand because it makes us feel this way too—it's a sound that lifts our own hearts when we hear it.

    What happens when a predator comes into their areas? The nearby birds quickly give an alarm call, a short sound that warns, “Danger is coming!” On hearing the sound, the other birds stop singing and fly for cover, the deer lift their heads and stop moving and the rabbits run into the bushes. Suddenly, the forest becomes silent.

    When humans walk through the woods in a hurry or while talking with a friend, we don't see much wildlife. We may think that there aren't many animals living there, but more likely, they know we are coming and hide minutes before our arrival. But if we learn to avoid setting off alarms, we can see many more wild animals without frightening them. To practice, find a place in a park and sit quietly for an hour. Take note as the birds begin to relax and sing again. When I do this, I am always surprised at the wonderful thing animals will do when humans simply stay still long enough.

    When was the last time you used plastic plates? Next time, why not try some edible ones? You'll help the environment and your guests won't go hungry. "I used to work in school catering and saw a lot of money being thrown away. I thought that was criminal, so I decided to do something about it," said Italian school chef Tiziano Vicentini.

    Now, Vicentini has an amazing range of edible plates for schools. The plates are made out of bread dough, so you can eat them afterwards. "These dishes cost a few pennies each and are either eaten by the kids, or go into recycling bins for animal food," explained Vicentini, 50, of Milan. But now other companies are developing edible plates, too. The Edible-Plate Company offers edible plates, bowls, trays and cups. Their products are environmentally-friendly, 100% biodegradable and can be used for all types of catering and home use. And they're made from a natural plant. After use, they can be fed to animals or left to degrade naturally.

    They also have a range of cutlery（餐具） made from corn and potato starch（淀粉）. These plates will also help reduce the amount of plastic; we create. Waste from plastic causes a lot of damage to the environment, as well as costing governments millions m waste management. Plastic bags often end up in landfill sites or on the street. And the burning of plastic waste causes toxic gases that pollute the air. In response to this, governments around the world are introducing tough recycling regulations. And many shops are offering biodegradable plastic bags and eco-safe packaging on their products. To help matters, the International Organization for Standardization (the ISO) has also developed a system to evaluate the biodegradability of products, with a certification and logo scheme, Meanwhile, how about a nice plate for lunch?

This morning, I saw the shocking headline: "Passenger Dies When Car Crashes in Driverless Mode". In the article, various people said that the public should oppose the idea of developing driverless cars. They said that some advances in technology were unnecessary and could even be dangerous. Hence, we should cease accepting technology just because it is new. The newspaper reported that the car company had already apologised for the accident, but the families of the deceased（死者）said it was not enough. Nevertheless, the company still claimed that most people would be travelling in driverless cars one day soon.

On the one hand, there are many different groups of people around the world who live happily in the absence of new technology. Probably the most well known are the Amish（亚米希人）,a group of Christians living in rural America. They do not own or drive cars, watch TV, or use the Internet. They have lived mainly as farmers since the 18th century, and they will probably be living the same way in the distant future. They advocate a simple life with an emphasis on hard work, family, and community. They think that is better than caring about luxuries or following the lives of the rich and famous. It could even be argued that the Amish's quality of life is better since they live in and appreciate the natural environment rather than living in large, polluted cities.

On the other hand, new technology has provided people everywhere with many benefits over the years. For example, the latest weather-tracking computer programmes give people lots of warnings about potential natural disasters, which saves many lives. Moreover, the Internet has made it possible for friends and family to keep in touch easily even if they are on opposite sides of the world. It has also made finding opportunities in life much easier, as it allows people to make larger networks of friends through using social media.

Personally, I have benefited quite a lot from technological advances. I found my career as an AI designer through a social media network. My health monitor, which I wear all the time, has also helped me get into the best shape of my life. Of course, when new technology changes the way we live, it can be a scary prospect.

Nevertheless, I will always look on the positive side of change and accept it rather than resist it.

 "BANG!" I pulled the door heavily behind me. "Never set foot in this house again!" stormed father. I rushed out of the flat and ran along the street.

A young man who held a child in his arms walked past me. I felt as if I saw my childhood from another space: happy and carefree. But now...I don't know whether it is because I have grown up or because Dad is getting old. We differ in our ways of thinking. We are just like two people coming from two different worlds. It feels like there is an iron(铁制的) door between us that can never be opened.

I wandered in the streets, until I had only the street lights to keep me company. My heart was frozen on this hot summer night. When I finally reached the high-rise apartment block in which I lived, I saw that the light was still on.

I thought to myself, "Is Father waiting for his boy, or still angry with him?"

All the lights were off except Father's.

Dad was always like this. Maybe he didn't know how to express himself. After an argument he had the habit of tucking me underneath the covers(掖被子) while I was sleeping. This was how he always was. He had been a leader for so long that telling everyone else what to do had become his second nature.

The light was still on.

"Am I wrong?" I whispered, maybe... With the key in hand, I was as nervous as I had ever been. At last, I decided to open the door. As soon as I opened the door, tears ran down my cheeks. I suddenly realized that the iron door that I had imagined between us did not exist at all. Love——it's second to none.