I stand outside waving at the car pulling slowly out of our driveway. I force a smile, hoping it will cover up my tearing eyes, but I know it's not working. I run into the house, slam the door behind me, and begin crying. It's just occurred to me that I can't see my elder sister, Monsura, in the next four months.

    I ask myself why it is that I'm crying when I know she's doing something good for herself. I feel selfish for thinking about it but I'd be lying if I said I was happy for her choosing to study in a university in Boston. When my brother, Shafat, left for college, it was different. I still had one sibling at home to call me the stupidest person on a daily basis.

    I am reminded of the things we did together as kids. In our old two-bed-room apartment, our parents gave in to our constant begging and traded rooms with us for one night. It was like being part of the amusement park, using our parents' big bed as a trampoline (蹦床).It was during the first night that I witnessed a full moon. My sister and I believed my brother. He said that the moon was yellow because it was made from cheese. We made plans to visit the moon so we could melt a part of it and make cheese dip. But now I laugh at myself for being so innocent.

    Sitting in front of my computer, I listen to songs that remind me of my two best friends. I come to terms with the fact that there's no longer anyone here to laugh uncontrollably with me or to turn to at night when I have a nightmare.

    I'm shaken into reality by the sound of my cell phone ringing. Shafat is calling. I pick up and he immediately says “Thank you for such a great childhood.'' Those few words mean the world to me. We three-way call Monsura and spend the next hour reliving memory after memory, and by the end, I forget that I'm alone at home.

    An American company has built a new drone（无人机）that could improve the speed of deliveries（送交的货）.

    The drone is very different from other unmanned aircraft.It is made almost completely out of cardboard and has no motor.It can be packed with materials and sealed up with tape.

    Because the drones do not have a motor,they are designed to be dropped from airplanes.Hundreds of drones could be sent out at once.Then they could be automatically guided to where they are supposed to go.The company says these drones could then complete deliveries to different places over an area covering hundreds of kilometers. The drones look bigger than the paper airplanes we used to make as kids.But this light flyer is not a toy.It is aerodynamically designed and equipped with a small computer,a battery and sensors to guide it to the ground.

    The drones are being developed by Otherlab—a technology research company in San Francisco,California.It calls the drone a "Sky Machine."

    The company says it can travel about 150 kilometers at speeds up to 88 kilometers an hour.Now,it can carry materials weighing up to one kilogram,but future models are expected to carry larger loads.

    One of the drone's main advantages is that it does not have a heavy motor or large battery.This allows more room for materials and makes the drone cost less to build and operate.

    The Otherlab development team has called its invention the "Ikea of drones".This is because it is packaged similarly to products from the Swedish furniture maker Ikea.The drone arrives as flat pieces of pre-cut cardboard that can be quickly and easily put together.

    The technology that guides the drone can make it land within 10 meters of its target,according to Otherlab. Unlike other drones,even a crash landing is acceptable.The company says the drones can also be reused.

    Once the drone completes its delivery,it can be thrown away and the cardboard material will likely break down within a few months.

    The company has received money from the U.S. Department of Defense to carry out research on the drones.The money came from the Defense Advanced Research Projects Agency.The agency is attempting to find the best delivery vehicles that can disappear after their missions are complete.The U.S. military has a need for delivery drones.But it wants to simplify and lower the cost of using them.Otherlab's Sky Machines are an attempt to fill that need.

    Military drones can also be stolen and studied by others if found after use.Before they can truly disappear,the electronic materials inside must also somehow disappear.Researchers are still working on ways to get the technology itself to self-destruct.

    Parents can cut the chances of their children getting fat simply by keeping them longer at table. Just three minutes extra at a family mealtime could help prevent child obesity. Research found that among poor families, the extra minutes at mealtimes made great improvement of a normal weight for the youth. The factors are likely to be communication and the importance of a scheduled mealtime.

    Dr Barbara Fiese said, “Children, whose families have a 20-minute meal over four times a week, weigh less than kids who leave the table after 15 to 17 minutes. Over time, those extra minutes per meal add up and become really powerful.”

    The researchers studied 200 family mealtimes, testing the effects of factors and mealtime behavior of families with children in primary school. They found that families, who said that shared mealtimes were an important part of family life and had special meaning for them, were less likely to have an obese child. Similarly, families, who talked more together and interacted more positively during the meal, were more likely to have healthy-weight children.

    Teaching low-income families how to make the most of family mealtimes was a wise idea. Dr Fiese said, “This is something we can target and teach.” She added, “It's also important to recognize the increasing differences of families and their sometimes complex living arrangements that may challenge their abilities to plan ahead and arrange a single time to communicate with each other.”

    Families in poorer US neighborhoods faced a lot of problems, including poor access to healthy food. But even so, regular high quality family mealtimes made a difference to the children's weight. Dr Fiese said, “Three to four extra minutes per meal will make a healthy weight more possible.”

    Bus Tours in Washington DC

    The Blossoms Tour In Washington DC

    Duration: 3 hours $56.99

    BEST WAY to Experience the Cherry Blossoms! Each year from mid March to mid April, see the beautiful Cherry Blossoms in Washington DC and get great photos because you'll be led to all the best spots by the best guides. The annual spring bloom in DC is a magical time and this tour promises to provide the very best tour opportunity for you!

    The Lights Night Tour in Washington DC

    Duration: 3 hours $56.33

    Highest-rated Night Tour in DC! The ONLY DC Night Tour where the Tour Guides HOP OFF with you at each stop and tell you about each monument and attraction. HOP aboard the The Lights Night Tour! The best time to take a tour of Washington DC is at night.

    The Best Minibus Tour in Washington DC

    Duration: 3 hours $ 46.92

    See all the key attractions DC has to offer in a 3-hour format. You will learn all about the history and trivia (琐事) that surrounds Washington and visit the major monuments and attractions DC has to offer.

    Please Note: Rates for this tour vary by day of the week. When you choose your specific date on the availability calendar, the rates for that date will be displayed.

Best Mount Vernon & Arlington Cemetery Tour from Washington DC

    Duration: 6 hours $ 78.96

    See Arlington Cemetery, Old Town Alexandria and George Washington's Mount Vernon Estate on this small group bus tour from Washington DC. Your tour guide will accompany you through Mount Vernon, telling you about all of the attractions there and the history of George Washington's home on the Potomac River.

    A shark moving around the coastline is normally a worrying sight，but this waterborne drone (无人机) threatens floating rubbish instead of people.

    Developed by Dutch company RanMarine, the WasteShark takes nature as its inspiration with its whale shark-like mouth. Responsible for collecting waste, the drone will begin operations in Dubai Marina in November after a year of trials with local partner Ecocoast.

    According to RanMarine, the WasteShark is available in both autonomous and remote-controlled models. Measuring just over five feet by three-and-a-half feet (1.5 meters by 1.1 meter), it can carry up to 352 pounds of rubbish (159.6 kg) and has an operational battery life of 16 hours.

    By 2016 there were approximately 150 million tons of plastic in the world's oceans. One paper from December 2014 estimated that over a quarter of a million tons of ocean plastic pollution was afloat.

    "WasteShark also has the abilities to gather air and water quality data, remove chemicals out of the water such as oil, and heavy metals, and scan the seabed to read its depth and outlines," said Oliver Cunningham, one of the co-founders of RanMarine. "Fitted with a collision-avoidance system, the drone uses laser imaging detection and ranging technology to detect an object in its path and stop or back up if the object approaches."

    "Our drones are designed to move through a water system, whether it's around the perimeter (周边) or through the city itself. The drones are that last line of defense between the city and the open ocean," added Cunningham. "WasteSharks are operating in Dubai, South Africa and the Netherlands and cost $ 17, 000 for the remote-controlled model and just under $ 23, 000 for the autonomous model."

    Dubai-based operator Ecocoast has two WasteShark drones. Co-founder Dana Liparts says they will clean waterfronts for clients including hotels and environmental authorities and that Ecocoast' intention is to have the collected rubbish recycled or upcycled. However, Liparts argues that cleaning waterways doesn't have a one-size-fits-all solution and requires a combination of new technology, preventative measures and changing people's attitudes towards littering.

    Anyone wanting to throw away their mobile phone can do it in style（时尚地）and may even win a medal－at the Mobile Phone Throwing World Championship.

    Originally a local event in a small town close to the Russian border, the fifteenth annual contest drew many throwers from as far as Canada, Russia and Belgium.

    Founder Christine Lund describes the event as a good source of light exercise with an environmentally-friendly activity. "There are a lot of mobile phones on the second-hand market, and we are recycling them（before they become poisonous waste）," she said.

    The inventive Finns had already given the world the Sauna World Championships and the Wife Carrying Competition before coming up with a new way to make mobile phones even more mobile.

    This year's gold medal went to Finland's Lassi Etelatalo, who threw a waste Nokia unit a forceful 89.00 meters. "I prepared by javelin（标枪）throwing, I haven't really practiced throwing mobile phones,"Etelatalo said.

    Lund says competitors all have their favorite throwing brand. "People choose by size, by color or by how it fits in the hand……Some believe a heavy model will ensure a long throw, some want a light one."