Americans drove more miles in 2015 than any year since the U.S. government started keeping records 45 years ago. The U.S. Department of Transportation (USDT) recently reported that Americans drove a record of 3.148 trillion miles last year. In case you are wondering, that is enough to take 337 round trips from Earth to Pluto.

    There are a number of reasons why Americans are driving more miles. The social experts agree that the first is the price of gas, which has dropped to the level of the year 2004 in the past year. The American Automobile Association (AAA) said that the average price of gas was just $1.71 a gallon. That could be the lowest price since 2004.

    P.J. Sriraj, a director of the Urban Transportation Center at the University of Chicago, notes that the lower cost to fill up a car is just one reason. Another reason is that more Americans are back to work after the 2008 economic recession, and they drive to their jobs.

    Besides, more Americans have to travel a long distance every day between home and the office. There are a lot of Americans who must travel more than 45 miles per day for their jobs. And as for many, there is not enough public transportation.

    Because of the heavy traffic, roads are becoming more and more crowded. While modern cars are more fuel-efficient, the improvement is not enough to offset more cars on the road. “There is no doubt that driving more will make the air dirtier,” said P.J. Sriraj. And many Americans showed a great concern in a recent survey.

    There is an old saying about volunteer work that goes like this: “ No one can do everything, but everyone can do something.”

    Today, many people volunteer their time and energy to help others. There are a lot of ways to meet other people's needs. For example, some volunteers provide help after a disaster. Others are happy to get dirty while repairing homes or planting trees or flowers in poor neighborhoods. Young people see suffering and loneliness around them and find ways to help. And history lovers help archeologists(考古学家) search for ancient objects to help deepen our knowledge of the past.

    Volunteers work in many areas around the world, including Haiti. More than four years have passed since a 7.0 earthquake shook the nation. The exact number of people who died may never be known. Thousands of survivors of the Haitian earthquakes still live in temporary shelters. Last year, former American President Jimmy Carter and his wife Rosalynn joined five hundred volunteers in the town of Leogane to build houses.

    Organizations do not have to be large to get volunteers. An activist group in Dharamsala, India is a good example, Jodie Underhill from England arrived in northern India several years ago. She planned to volunteer for an environmental project. She could almost not believe how much rubbish was ruining some of the area's most beautiful sights. Jodie Underhill learned about how to deal with the rubbish while taking part in other volunteer projects. But soon enough she formed her own group, Mountain Cleaners. Jodie Underhill says the work is very hard. But she praises the group's efforts as a wonderful experience. The young Englishwoman says the Indian media started calling her “Garbage Girl”. And she says she was pleased with the name.

    American teenagers also volunteer in many ways .

    Benito Juarez, a poor Indian boy, was twelve years old when he left his village home in December 1818.Benito walked forty-one miles to the city of Oaxaca, high in the mountains of Mexico. When he heard the Spanish spoken by the city people, Benito didn't know what they were saying.

    First, Benito became a servant for a wealthy gentleman, Serer Maza. Soon, he went to work for Antonio Salanueva ,a church(教会)librarian. Antonio repaired and copied the library books, keeping them in good shape.  Benito became his helper and his housekeeper. Antonio loved to teach. Benito soon became his student as well as his servant. With the help of Antonio, Benito learned to speak, read, and write Spanish.

    At that time in Mexico, many people believed that Indians were not smart enough to read or learn. Antonio knew that was not true. Indians had been prevented from learning by a lack of schools. The first Spanish missionaries(传教士)who came to Mexico had educated the native people. In fact, churches from Spain had built the first college on the North American continent(大陆)for the Indians. As more Spanish came to Mexico, however, the Indian children were crowded out of the schools.

    Benito was a good and bright student, so Antonio developed a plan for him. In 1821, when Benito was fifteen, Antonio decided to enroll him in a school for boys. Antonio taught Benito what he needed to pass the entrance test for the school.

Benito became a student at the college. His studies were difficult, and he was teased because he was the only Indian student there. He succeeded in spite of these challenges. Later, as the laws changed, Benito was able to attend a public college with other Indians.

    Benito Juarez continued his education and became a lawyer and, much later, the President of Mexico from 1861 to 1872. He led the Mexican people to victory over the French, who tried to rule Mexico, and fought for the rights of Indians. He is one of the great heroes in Mexican history.

    Google's new camera, called Clips, is a small, smart device. It comes with a case that has a clip (夹子)，but it's not designed to be worn on your clothing. Most interestingly, it uses artificial intelligence to take photography out of your hands so it can capture moments on its own.

    This roughly 2-inch by 2-inch camera, with a three-hour battery life and Gorilla Glass for toughness, is intended for candid moments, like when a child does something cute that may happen too quickly for you to pull out your smartphone.

On board the Clips device, it uses machine learning algorithms (计算程序) to help capture scenes. Those algorithms include face recognition. “Once it learns that there's a face you see frequently, it'll try to get nice photos of those faces,” said Juston Payne, the device's product manager. And they also want it to recognize facial expressions, which involved “training it to know what happiness looks like”. The Google team also trained it to recognize what not to shoot — like when a child's hand is over the lens, or if it is tossed in a dark purse.

    The only way to see the images is by connecting the camera with your phone, as it has no screen for viewing or editing.

    Were people concerned it could seem strange? Yes, Payne admitted. But they said they addressed that by making it obvious what it is. A green light on the front signals that it is on. Besides, unlike a camera meant to monitor your home, it is not connected to the Internet.

    “This product is only possible because of the way that silicon has advanced” Payne said, noting that it was only in the past year or so that they could squeeze the technology down into a device this size. Going forward, we're likely to get more assistance from the artificial intelligence packed into our apps and gadgets.

    When I got home after dropping out of college in my junior year because of depression, I didn't want to get out of bed. But my parents wanted me to, so I just transferred myself to the couch in the living room. Sometimes I would turn on the TV and watch marathons of Chopped, but mostly I just sat there, lost in thought.

    One day when I was lying on the couch, not knowing what to do, I wondered since I had been out of school for a long time, I might as well do something productive with my life. I looked at my options. I could attend some kind of online college class, go to in-person events just to get out of the house, or take up a hobby. But none of these things made me happy, and my depression seemed to keep me drowning under the waves.

    There was something that was my thing—entrepreneurship. No matter what kind of day I'm having now, the mere mention of start-ups still perks me up. I have been starting business in some kinds of forms ever since I was a kid, and despite everything, this passion has never changed.

    So I started thinking of ideas, seeing which one could become practical business. I spent my days glued to a wide purple notebook, a pen in hand, sometimes moving from the couch to the table on our back porch in the mornings. If I got up early enough, I'd watch the sun come up. It was there, in the still mornings, that I learned about life and started to look back on mine.

    With time going on, the depression started to lift. I was making more progress in my recovery, and the good days were more frequent than the bad. I started a couple of different businesses, eventually settling on a web design business, and did a lot of experiments and changed my ideas, and after a while, things started to work.

    For as long as we've known about it, humans have searched for a cure for cancer. Across the world, countless amounts of time and money have been spent on researching a way to stop this terrible disease. But now, it seems like the answer could have been inside our own bodies the whole time.

    Recently, the Food and Drug Administration (FDA) in the US, a government agency that's responsible for healthcare, approved a new form of gene therapy (疗法) that could mean the end of a certain type of cancer.

    The therapy allows scientists to "train" the immune (有免疫力的) cells of sick patients to fight leukemia (白血病)—a form of blood cancer that mostly affects young people.

    The exciting new treatment works by removing healthy immune cells from the patient, known as T-cells, which are then changed to be able to "hunt down" cancer cells.

    The cells are then put back into the patient before they begin to get rid of the patient's leukemia over time, similar to how the body fights off other illnesses.

    "This is truly an exciting new day for cancer patients," Louis J. DeGennaro, president of the Leukemia and Lymphoma Society, said in a news release.

    Up until now, a long and painful marrow transplant (骨髓移植) was the only option for many leukemia patients.

    In this procedure, healthy blood cells are taken from a donator and placed into the sick patient, who also has to go through chemotherapy (化疗) to allow their body to adjust to the new cells.

    But with a recovery rate of around 83%—according to a news release published by the FDA—it's hoped that the days of painful trips to the hospital, or even death, are over for leukemia sufferers.

    "We're entering a new frontier in medical innovation (创新) with the ability to reprogram a patient's own cells to attack a deadly cancer," FDA representative Scott Gottlieb said in the release. "New technologies such as gene and cell therapies hold the potential to transform medicine and our ability to treat and even cure many incurable illnesses."