We're often reminded of the importance of preserving the planet as we see it for future generations—and children at St Oswald's Primary School in Chester certainly agree.

    Nine-year-old Isobel Kelleher from the school's Hummingbirds class thinks adults need to take note. “Sometimes they can be busy and I don't think they think they can make a difference，but if everyone does a little bit it all adds up，” she tells HuffPost UK.“ We started looking at plastic pollution in our oceans and the things like plastic bags and broken down pieces of plastic that are polluting them.” she says.“ Fish can eat the plastic and they can die，or we might even eat the fish ourselves.”

    Mr Timms，Isobel's teacher，has been spearheading a new project at the school which lets children loose creatively to raise awareness of the need to be more environmentally friendly. The entire Hummingbirds class，which is made up of 9 and 10-year-old pupils，has been busy writing poems and creating online video adverts to warn adults about the serious situation of our oceans and wildlife.

    Mr Timms thinks children have an important role to play in teaching us how to take care of the things around us. We sometimes overlook how much we can really learn from children.” he says.“ It has been really hard to believe having parents come in saying that their children have been asking them to stop using plastic，and to recycle more，and even stopping them using plastic straws.”

    Mr Timms is proud of his Hummingbirds class.“ The message that they would like to send to the world is simple stopping this isn't someone else's job，and it won't be OK if we just leave it.”

    After decades of cat-and-mouse between athletes and the word anti-doping agency (WADA), athletes found what they must have believed to be the ultimate (终极的) doping agent: their own blood. To enhance athletic performance with your own blood, you draw your blood and store it in a freezer. Your body compensates by creating more blood. Then, months later, just before a competition, you can re-inject (注射) the old blood for a boost. As the red-blood-cell count goes up, so does an athlete's ability to absorb oxygen. The more oxygen you get with each breath, the more energy your body is able to bum and the better you are able to perform.

    Although the enhancement is small compared to actual drugs, it can be the difference between a gold medal and a silver medal. Best of all, "extra blood" was never something WADA tested for.

    But WADA wasn't going to sit by and be fooled. What it came up with in response might be a solution to stop doping once and for all: an athlete biological passport (ABP). The idea is to record some biological features of an athlete through testing done at regular intervals. The biological passport's partial implementation (实施)—recording blood and steroid levels—began in January 2014.

    When all necessary biological features are finally combined, WADA will no longer need to worry about finding new methods to detect a drug. It will only have to detect (检测) resulting changes in the body. In the case of blood doping, if the athlete's normal red-blood-cell count is, say, 47%, but then is found to be 51% after a competition, cheating may have been involved.

    WADA is confident that the biological passport could even prevent genetic changes—the ultimate, ever-lasting enhancement—which are surely coming next. If an athlete inserts a performance enhancing gene, it will probably leave detectable changes in the body, that would differ from the athlete's feature in the biological passport.

    Abraham Lincoln, a self-taught lawyer, was elected 16th president of the United States in November 1860, shortly before the outbreak of the Civil War. Lincoln proved to be a smart military strategist and a competent leader: His Emancipation Proclamation (解放宣言) paved the way for slavery's abolition, while his Gettysburg Address stands as one of the most famous speeches in American history. In April 1865, with the Union on the brink of victory, Abraham Lincoln was killed; his untimely death made him a hero to the cause of liberty, and he is widely regarded as one of the greatest presidents in U.S. history.

    On January 20, 1981, Reagan took office. Only 69 days later he was shot by a would-be killer, but quickly recovered and returned to duty. His grace and wit during the dangerous incident caused his popularity to soar.

    At the end of his two terms in office, Ronald Reagan viewed with satisfaction the achievements of his innovative program known as the Reagan Revolution, which aimed to motivate the American people and reduce their reliance upon Government. He felt he had fulfilled his campaign pledge of 1980 to restore "the great, confident roar of American progress and growth and optimism."

    When George W. Bush, at the age of 54, became the 43rd president of the United States, it was only the second time in American history that a president's son went on to the White House. John Quincy Adams, elected the sixth president in 1824, was the son of John Adams, the second president. While John Adams had brought up his son to be president. George Bush, the 41st president, insisted he was surprised when the eldest of his six children became interested in politics, became governor of Texas, and then went on to the white House.

    Barack Obama served as the 44th President of the United States. His story is the American story—values from the heartland, a middle-class upbringing in a strong family, hard work and education as the means of getting ahead, and the belief that a life so blessed should be lived in service to others.

    With a father from Kenva and a mother from Kansas, President Obama was born in Hawaii on August 4, 1961. He was raised with help from his grandfather, who served in Patton's army, and his grandmother, who worked her way up from the secretarial pool to middle management at a bank.

On paper, hydrogen (H2) looks like a dream fuel. Coal, oil, and natural gas produce carbon dioxide, which warms the earth when burned, Hydrogen produces pure water. Hydrogen packs more energy into less space than a battery (but certainly less than petrol) . Also, empty tanks (燃料箱) can be refilled with hydrogen much faster than refilling empty batteries with electricity.

While in practice, things are trickier. Storing a meaningful amount of hydrogen gas requires pressing it several hundred-fold. Changing it into the liquid form is another option, but it should be cooled to-253C. Both processes require a heavy and strong tank. While a 700 bar tank is acceptable for a city bus or a truck, adapting it for use in small vehicles is very difficult because the pressure during refilling would be too great.

The solution? Powerpaste.

A German team of researchers, led by Marcus Vogt, have come up with an interesting "powerpaste", which can store hydrogen energy at atmospheric pressure, ready for release when needed. It is so named because it comes in tubes and looks like toothpaste (牙膏) , not in its traditional form of gas.

The main ingredient (原料) of the paste is magnesium hydride, a substance that reacts with water to form hydrogen. The escaped hydrogen can then be directed into a fuel cell, where it reacts with oxygen from the air to produce electric power.

Refueling is very simple, as instead of going to a filling station, drivers and riders can simply replace an empty tube with a new one and refill the water tank.

Given that powerpaste only begins to break down at temperatures of around 250℃ it remains safe even when a vehicle stands in the baking sun for hours.

However, we will have to be patient. Just because researchers have succeeded in developing a new fueling way does not mean that we can expect to see such vehicles on the road anytime soon. It will indeed be several years before this concept is turned into reality.

Iˈve always loved the ocean. In the {#blank#}1{#/blank#} (seven) grade, I started volunteering at the Monterey Bay Aquarium in California. I was upset to learn that many sea animals eat plastic garbage, {#blank#}2{#/blank#} (think)it is food. 

I decided to do something {#blank#}3{#/blank#} (educate) people about this problem. I held presentations at schools to teach kids about plastic waste. I wanted to reach businesses too. I decided that if I learned of a company{#blank#}4{#/blank#} used a lot of plastic, Iˈd send it an email urging it to cut back. 

One day, I saw a commercial for a health-care company. People in the ad were using plastic straws （吸管）. I found the contact information of the company{#blank#}5{#/blank#} emailed its president. I told him how {#blank#}6{#/blank#} (harm) plastic could be to the environment and asked him to consider using more eco-friendly options. I was so{#blank#}7{#/blank#} (excite) when he wrote back to me. He said he would make sure that the company cut its use of plastic straws in half. 

I kept going. Whenever I heard of businesses using plastic, Iˈd send an email. One of the biggest companies I wrote to {#blank#}8{#/blank#} (be) Alaska Airlines Paris. A company{#blank#}9{#/blank#} (represent) wrote back and told me the airline was switching over{#blank#}10{#/blank#}plastic to paper cups on all of its 1, 200 daily flights.