The following properties which the World Heritage Committee(世界遗产委员会) has decided to include on the List of World Heritage are under threat.

     Cultural Landscape and Archaeological Remains of the Bamiyan Valley (Afghanistan)

    The cultural landscape and archaeological remains of the Bamiyan Valley stand for the artistic and religious developments which from the 1st to the 13th centuries characterized ancient Bakhtria. The area contains a number of Buddhist monastic ensembles, as well as strong buildings from the Islamic period.

     Historic Centre of Vienna (Austria)

    Vienna developed from early Celtic and Roman settlements into a Medieval and Baroque city, the capital of the Austro-Hungarian Empire. It played an important role as a leading European music centre, from the great age of Viennese Classicism through the early part of the 20th century. The historic centre of Vienna is rich in architectural buildings, including Baroque castles and gardens, as well as thelate-19th-century Ringstrasse lined with grand buildings, monuments and parks.

     Okapi Wildlife Reserve (Democratic Republic of the Congo)

    The Okapi Wildlife Reserve occupies about one-fifth of the Ituri forest in the northeast of the Democratic Republic of the Congo. The Congo river basin, of which the reserve and forest are a part, is one of the largest drainage systems in Africa. The reserve contains threatened species of primates and birds surviving in the wild. It also has some amazing scenery, including waterfalls on the Ituri and Epulu rivers. The reserve is inhabited by traditional nomadic pygmy Mbuti and Efe hunters.

    "We said no to the invitation to the birthday party because my child says they're not even friends."

    When I read the above words, I felt heartache.

    I know birthday parties can be like a trouble, but let's believe the parents who sent that invitation weren't trying to get more gifts for their kids or make things more complicated(复杂的).

    For some kids, managing school and friends is easy. Maybe you have a child who's outgoing, self-confident or maybe you have a child who doesn't have any problems. However, for some kids, school and friends can be very difficult.

    A birthday party is a fun, exciting and good opportunity. It is a chance for the kid on the sidelines to play with other kids who don't play with him/her at school or who don't call him/her a friend.

    Sometimes even when the birthday party and the theme have been decided on and the difficult decision about whom to invite has been made, there can still be doubts. Those invitations can stay untouched in the bottom of the child's backpack for days, because he/she is too scared to hand them out.

    I don't know your child, and I don't know you. I do know there are parents who lie awake at night wondering if their children will have the courage to hand out the invitations in the morning; I do know there are parents who hope they can depend on other parents to teach their children to be kind enough to show up. Maybe you'll never have to be one of the parents who find it hard. I know what that's like, because I have children who find it easy. But I also have a child who doesn't. And because of that, we've become a family that says yes to every invitation we receive.

    Sometimes a birthday party invitation is not just a birthday party invitation; it's also an invitation to be a friend.

    When you're sitting in class or behind your desk waiting for the clock to strike a time when you can go home, it is natural that your mind should wander a bit. It is common for your mind to wander to a vacation and even travel the world. What if there is a way that you can travel the world without having to pay any money?

    A person that managed to make it around the world without spending much was Shantanu Starick. How did he trade off his service? Starick realized that as a photographer he had a service that people would usually be willing to pay money for, but he would instead offer his photography service to anyone who could provide him with food, shelter and transportation. Starick has been traveling for a surprising 30 months and has visited countries ranging fromthe United States to Ecuador.

    In English-speaking countries, trading off services and communicating aren't difficult for Starick. However, in farther areas where there isn't an English-speaking person in sight it can be quite difficult. More than anything, the locals appreciate the effort behind trying to speak their language, even if he doesn't exactly sound like a native speaker.

    You can do it too!

    Honestly, with a bit of confidence, drive and a skill you can trade, you'll be able to do exactly the same as Starick.

    Start thinking about what you can do to get around the world without paying money. With our social networks and the connectivity our world has, you can easily connect with and market yourself to people across the world without any effort.

    In the coming decade, space agencies and private space companies like SpaceX are planning to build a base on the Moon and Mars. While scientists are already building rockets for the journey, for long-term human settlements on them, astronauts will need fuel to carry out daily tasks. Many have suggested hydrogen. But a group of scientists is working on turning CO ₂ in the atmosphere into jet fuel. As Mars is rich in CO ₂ and the lunar surface has a high concentration of CO ₂, it may be a feasible solution.

    For now, though, the team of scientists at the University of Oxford is focusing on making jet fuel for the aviation (航空) industry. As the aviation industry releases over 900 million tons of CO ₂ every year, to battle climate change, it is necessary to turn the tide. So far aviation scientists have tried to use other energy resources like electricity to fly. But such flights are limited to short distances. For long-distance flights, there is no alternative yet.

    The concept of turning CO ₂ into jet fuel is not new. Previously, other similar methods had to rely on expensive catalysts (催化剂) like cobalt to speed up the chemical reaction. But what Oxford scientists suggest is adding a cheap iron-based catalyst and hydrogen to turn CO ₂ into liquid fuel. As the process would not involve using fossil fuel, it will make the industry carbon neutral(碳中和的).

    The scientists tested the new catalyst in a lab at 300℃ and at 10 times the air pressure at sea level. The entire process took 20 hours and turned 38 percent of CO ₂ into new chemicals. About 48 percent of the chemicals were jet fuel hydrocarbon and the rest were other by-products that are used in the production of plastic.

    Professor Peter Edwards, a lead scientist in the project, said the new method could be improved in two to three years to produce jet fuel in large quantities. "This is a really exciting, potentially revolutionary advance. Our vision is that the world can see that CO ₂ collected can be used as an energy carrier to enable sustainable aviation."

    I get up in the dark hours of the morning for three reasons only: to attend ANZAC Day service, to     1    a cheap flight, or to witness an astronomical(天文的) event. It was the last of the three that pushed me to set my     2    for 3 a.m. on Sunday May 8 this year.

    I was     3    at my best friend's place in the Blue Mountains, west of Sydney. That morning it was so cold. I got out of bed before I had time to change my     4    . I grabbed a jacket and headed outside, pausing at the corner of the cottage to     5    . The Milky Way was blazing(闪耀) in a cloud-free sky and within seconds a shooting star     6    across my field of view. Then I woke up my friend and     7    her it would be worth her while. She had not been as     8    as me. Only one minute later I saw the next shooting star. I     9    , "There!" "Where?" "Over there!" I said,      10    as though it could help. "There's another!" She was     11    to get excited. The rewards were coming from all     12    now. We observed some ten more stars within minutes, most     13    before one of us could draw the other's attention.

    An hour and a half—and several dozens of shooting stars—later, my friend and I were cold and     14    we had seen enough.     15    at what had felt like our own private show, we held our arms tightly and headed back to the cottage.